Revert "Revert "block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAIT""

This reverts commit bba91cdb which is
commit b0beb280 upstream.

It breaks things in 5.4.y, so let's drop it.

Reported-by: Andres Freund <andres@anarazel.de>
Cc: Bijan Mottahedeh <bijan.mottahedeh@oracle.com>
CC: Jens Axboe <axboe@kernel.dk>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>