[PATCH] ppc32: fix build with oprofile

Current -git tree doesn't build when enabling oprofile on a non-bookE CPU
(like on a PowerMac for example).  While there is no performance counter
support for these CPUs implemented yet, it's still nice to be able to use
the timer based sampling, and that got broken.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>