powerpc: Drop return value from set_breakpoint as it is unused

None of the callers check the return value, so it might as
well not have one at all.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --cc arch/powerpc/include/asm/debug.h
Simple merge

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