nds32: add support for TIF_NOTIFY_SIGNAL

[ Upstream commit b13e8bf6 ]

Wire up TIF_NOTIFY_SIGNAL handling for nds32.

Cc: Nick Hu <nickhu@andestech.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>