c6x: add support for TIF_NOTIFY_SIGNAL

[ Upstream commit 6d665a4d ]

Wire up TIF_NOTIFY_SIGNAL handling for c6x.

Cc: linux-c6x-dev@linux-c6x.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>