[PATCH] powerpc: oprofile support for POWER6

POWER6 moves some of the MMCRA bits and also requires some bits to be
cleared each PMU interrupt.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>