powerpc: Fix incorrect PPC32 PAMU dependency

The Freescale PAMU can be enabled on both 32 and 64-bit
Power chips. Commit 477ab7a1 restricted PAMU to PPC32.
PPC covers both.

Signed-off-by: Andy Fleming <afleming@gmail.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>