Thinkpad R60 hangs when booting recent 8.4-STABLE

[Don Lewis]

On 28 Apr, To: stable at freebsd.org wrote:
> I've been upgrading my 8.4-STABLE machines to r264698 and haven't had
> any issues until I tried to upgrade my laptop.  I was previously running
> r259528 without any problems, but it now hangs during boot.  It's a hard
> hang and the machine doesn't respond to anything, including Caps Lock.
> I took a picture of the screen and compared it to dmesg.boot from
> booting kernel.old and the boot messages appear to be identical up to
> the point where the hang occurs.

I received a hint offline to look at r262226, which tweaked
sys/dev/pci/pci.c.  A r262225 kernel boots fine, but r262226 hangs.
I didn't suspect that commit because realloc_bars is set to 0.

I see that there is already a PR for this: kern/kern/188534.