sh: add support for TIF_NOTIFY_SIGNAL

[ Upstream commit 6d3a2733 ]

Wire up TIF_NOTIFY_SIGNAL handling for sh.

Cc: linux-sh@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>