powerpc: Make load_hander handle upto 64k offset

If we change load_hander() to use an ori instead of addi, we can load handlers
upto 64k away provided we are still 64k aligned.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --cc arch/powerpc/include/asm/exception-64s.h
Simple merge

diff --cc arch/powerpc/kernel/exceptions-64s.S
Simple merge

diff --cc arch/powerpc/kernel/setup_64.c
Simple merge