um: add support for TIF_NOTIFY_SIGNAL

stable inclusion
from stable-v5.10.162
commit dc808ffd9778aa013c792bb2ed369b84e346b67f
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7P7OH

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=dc808ffd9778aa013c792bb2ed369b84e346b67f



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[ Upstream commit a5b3cd32 ]

Wire up TIF_NOTIFY_SIGNAL handling for um.

Cc: linux-um@lists.infradead.org
Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>