powerpc: Rename __get_SP() to current_stack_pointer()

Michael points out that __get_SP() is a pretty horrible
function name. Let's give it a better name.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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

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

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

diff --cc arch/powerpc/kernel/misc.S
Simple merge

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

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

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