PPC upstream kernel ignored DABR bug

[Roland McGrath]

The G5 that I have says:

	cpu             : PPC970FX, altivec supported
	revision        : 3.0 (pvr 003c 0300)

and it does indeed reproduce this bug.

It also strange for it to be the DABRX issue given the failure mode.
That is, it works sometimes but unreliably (as if the context switch
sometimes fails to install the value).


Thanks,
Roland