UPSTREAM: block: add plug while submitting IO

So that if caller didn't use plug, for example, __blkdev_direct_IO_simple()
and __blkdev_direct_IO_async(), block layer can still benefit from caching
nsec time in the plug.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20240509123825.3225207-1-yukuai1@huaweicloud.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>

Bug: 374236878
Change-Id: Ic10a00fd446c7f39da7eea505f015137a911e04d
(cherry picked from commit 060406c6)
Signed-off-by: Yang Yang <yang.yang@vivo.com>