UPSTREAM: 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
Change-Id: I0e38ee478eff25064bb03277a29ba273b0656b28
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit c82617d9)
Bug: 268174392
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>