block: Delete bio_prio()

Since commit 43b62ce3 ("block: move bio io prio to a new field"), macro
bio_prio() does nothing but return the value in bio->bi_ioprio. Most other
places just read bio->bi_ioprio directly, so replace bi_ioprio() callsites
with reading bio->bi_ioprio directly and delete that macro.

Signed-off-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20241202111957.2311683-2-john.g.garry@oracle.com


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