11.1 release CD image panics very early during boot on ppc.

[Jukka Ukkonen]

I had a bit of an accident with my old PowerMac G4 which had been
running FreeBSD-10.4. To fix the mess I had to boot the system from
a CD image. So, I decided to try 11.1 while at it. To my astonishment
and disappointment the 11.1 images (both CD and DVD) paniced
very early on during the boot. The messages flashed past the screen
so quickly that I cannot be really sure about anything, but it kind of
seemed like the issue might be yet another installment of the SPRG
related problems (in ofw_machdep.c) which have been troubling
ppc64 systems before.
The 10.4 CD image boots just fine on ppc.

--jau