Afb cleanup and luna68k support (Re: Color support for wsfb/Amiga)

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

I wrote:

> > It would be great if we can support color X server on luna68k, which
> > also has "planer" framebuffer.
> 
> It has been in my TODO long time, but I'll check if at least 8bpp one
> on my LUNA-II works, after current other tasks (atari and x68k etc.)
> are done.

Finally I've tried Afb planar changes on my LUNA-II with 8bpp board.

It just works fine, but I had to fix several implementation and
would like to commit several these changes.

My local changes are here:
 https://github.com/tsutsui/netbsd-xsrc/commits/xf86-video-wsfb-reorganize

As noted in the above change logs there include:

1) proper XORG_VERSION_CURRENT checks for HAVE_XORG_SERVER_VER=110 ports
   and define explicit "HAVE_SHADOW_AFB" macro for maintainability
 https://github.com/tsutsui/netbsd-xsrc/commit/9964f0d15d6e7c6898edeedab4125dd17b7e0277

2) fix mmap size length in planar cases without WSDISPLAYIO_GET_FBINFO
   (rin@ said amiga occationally worked because fbi_fbsize was preferred)
 https://github.com/tsutsui/netbsd-xsrc/commit/da2f3ff6283590a3af7dc4feeaa89ef05a407b9a

3) luna68k 8bpp planar support
 https://github.com/tsutsui/netbsd-xsrc/commit/1e81576540a0e308d6ef9cb7e2e5abe14d823ca9

Furthermore, I've tried to reduce diffs from upstream xf86-video-wsfb:

4) try to reduce diff from recent upstream xf86-video-wsfb
 https://github.com/tsutsui/netbsd-xsrc/commit/2c08eac8a598a14b0385833f5ca45be8c87a3fa6
 - I wonder if we should also move xf86SetDefaultVisual() and
   xf86SetGamma() calls as upstream, though

5) use proper conditionals for xf86DisableRandR()
 https://github.com/tsutsui/netbsd-xsrc/commit/07981639474ccc71667d157ace3866c9e79cc14f
 - not sure if this gives benefits on XORG=110, just taken from
   other xf86-video drivers

If there is no particular objection, I would like commit theses changes
in a few days.

Thanks,
---
Izumi Tsutsui