loop: clean up grammar in warning message

The phrase "has still" should be "still has" to clean up the grammar.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20220208114656.61629-1-colin.i.king@gmail.com


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