[POWERPC] Added kprobes support to ppc32

Added kprobes to ppc32 platforms that have use single_step_exception.  This
excludes 4xx and anything Book-E since their debug mechanisms for single stepping
are completely different.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

diff --cc arch/powerpc/Kconfig
Simple merge

diff --cc arch/powerpc/kernel/kprobes.c
Simple merge

diff --cc arch/powerpc/lib/Makefile
Simple merge

diff --cc include/asm-powerpc/kprobes.h
Simple merge

diff --cc include/asm-powerpc/sstep.h
Simple merge