x86: tracehook: TIF_NOTIFY_RESUME

This adds TIF_NOTIFY_RESUME support for x86, both 64-bit and 32-bit.
When set, we call tracehook_notify_resume() on the way to user mode.

Signed-off-by: Roland McGrath <roland@redhat.com>

diff --cc arch/x86/kernel/signal_32.c
Simple merge

diff --cc arch/x86/kernel/signal_64.c
Simple merge

diff --cc include/asm-x86/thread_info.h
Simple merge