radeonfb.c change for Mac Mini

[MOCHIDA Shuji <mochid%netside.co.jp@localhost>]

My Mac Mini, used to work with 6.1_STABLE kernel, now works with
new radeonfb.c of current. I'm very happy with that, thank you very much.

  http://mail-index.netbsd.org/source-changes/2018/06/28/msg096400.html

Though, my LCD panel via DVI has dots 1600x1200, when switching to radeonfb,
shrink to 1024x768.

ofctl -p output related to that below.
width x height 640h x 4b0h  -- 1600x1200

any comments appreciated.

-mochid


% dmesg
      :
[   1.0000000] NetBSD 8.99.21 (BASS1) #0: Sat Jun 30 20:01:53 JST 2018
      :
[   1.0000000] bootpath: /pci@f4000000/ethernet:/netbsd.n
[   1.0000000] mainbus0 (root)
[   1.0000000] cpu0 at mainbus0: 7447A (Revision 1.2), ID 0 (primary)
[   1.0000000] cpu0: HID0 0x84d0c1bc<EMCP,TBEN,HIGH_BAT_EN,NAP,DPM,ICE,DCE,XBSEN,SGE,BTIC,LRSTK,FOLD,BHT>, powersave: 1
[   1.0000000] cpu0: 1250.00 MHz, 512KB L2 cache no parity
      :
[   1.0000000] radeonfb0 at pci0 dev 16 function 0: ATI Technologies Radeon 9200 5962 (rev. 0x01)
[   1.0000000] radeonfb0: Video BIOS not present
[   1.0000000] radeonfb0: No video BIOS, using default clocks
[   1.0000000] radeonfb0: refclk = 27.000 MHz, refdiv = 12 minpll = 125000, maxpll = 400000
[   1.0000000] radeonfb0: 64 MB aperture at 0x98000000, 64 KB registers at 0x90000000
[   1.0000000] radeonfb0: display 0: initial virtual resolution 1024x768 at 8 bpp
[   1.0000000] radeonfb0: using 32 MB per display
[   1.0000000] radeonfb0: port 0: physical 1024x768 59Hz
[   1.0000000] radeonfb0: port 1: physical 1024x768 59Hz
[   1.0000000] wsdisplay0 at radeonfb0 kbdmux 1: console (fb, vt100 emulation)
      :

% ofctl -p
[Caching 118 nodes and 891 properties]
ff891a00: /device-tree

#address-cells          00000001 ........ ........ ........     1
#size-cells             00000001 ........ ........ ........     1
AAPL,add-fcode-file     ff869f30 ........ ........ ........   ...0
clock-frequency         09ec5815 ........ ........ ........   166.483MHz
compatible              506f7765 724d6163 31302c31 00......   "PowerMac10,1"
            000d:       4d616352 49534333 00...... ........   "MacRISC3"
            0016:       506f7765 72204d61 63696e74 6f736800   "Power Macintosh"
            0026:       00...... ........ ........ ........   ""
copyright               436f7079 72696768 74203139 38332d32   Copyright 1983-2
            0010:       30303420 4170706c 6520436f 6d707574   004 Apple Comput
            0020:       65722c20 496e632e 20416c6c 20526967   er, Inc. All Rig
            0030:       68747320 52657365 72766564 00......   hts Reserved.
customer-sw-config      20202020 20202020 20202000 ........              .
device_type             626f6f74 726f6d00 ........ ........   "bootrom"
display-config-info     00000000 00000001 ........ ........   ........
model                   506f7765 724d6163 31302c31 00......   "PowerMac10,1"
name                    64657669 63652d74 72656500 ........   "device-tree"
      :
serial-number           52485400 00000000 00000000 00594d35   RHT..........YM5
      :

ff8947b0: /cpus/PowerPC,G4@0

altivec                 
available               00003000 7fffd000 d0000000 20000000   ..0......... ...
bus-frequency           09ec5815 ........ ........ ........   166.483MHz
clock-frequency         4a817c7b ........ ........ ........   1.249GHz
      :

ff897938: /aliases
      :
agp                     2f706369 40663030 30303030 3000....   /pci@f0000000.
      :
screen                  2f706369 40663030 30303030 302f4154   /pci@f0000000/AT
            0010:       592c526f 636b486f 70706572 32506172   Y,RockHopper2Par
            0020:       656e7440 31302f41 54592c52 6f636b48   ent@10/ATY,RockH
            0030:       6f707065 72325f41 403000.. ........   opper2_A@0.
      :

ff9d6ce8: /pci@f0000000/ATY,RockHopper2Parent@10/ATY,RockHopper2_A@0

EDID                    00ffffff ffffff00 26cd0048 47000000   ........&..HG...
      :
depth                   00000008 ........ ........ ........   ....
device_type             64697370 6c617900 ........ ........   "display"
display-type            4c434400 ........ ........ ........   LCD.
height                  000004b0 ........ ........ ........   ....
      :
name                    4154592c 526f636b 486f7070 6572325f   "ATY,RockHopper2_
            0010:       4100.... ........ ........ ........   A"
      :
width                   00000640 ........ ........ ........   ...@
      :