block/mq-deadline: Use the new blk_opf_t type

Use the new blk_opf_t type for an argument that represents a bitwise
combination of a request operation and request flags. Rename that
argument from 'op' into 'opf'.

This patch does not change any functionality.

Cc: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-9-bvanassche@acm.org


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