current broken on 486

[Felix Deichmann <m4j0rd0m0%gmail.com@localhost>]

Hi,

I tested current against a 486DX2/66 with 48 MB RAM and a 486DX/33 with
24 MB RAM, and it is broken.
Tried a GENERIC_TINY kernel, a GENERIC_TINY kernel with options DDB and
DIAGNOSTIC, and also GENERIC (on the DX2 with more RAM only).

In all cases the machines panic right after "cpu0 at mainbus0" with a
"uvm_fault" and "fatal page fault in supervisor mode".
Unfortunately I cannot get into ddb, the machines will hang or reboot
after printing the lines as in this log via serial console:

	http://www.netbsd.org/~flxd/486_console_20161207.txt

Following the addresses after "eip" with nm or the map file gives:

nm:
	0xc0119b5f	cpu_get_tsc_freq
	0xc012828d	lapic_initclocks

netbsd.map:
	c0119bac t cpu_attach
	c0128338 t i82489_icr_wait

HTH (but don't understand why they differ?)...
NetBSD 7.0.1 works on aforementioned machines.

Felix