md/raid5: Use the enum req_op and blk_opf_t types

Improve static type checking by using the enum req_op type for variables
that represent a request operation and the new blk_opf_t type for
variables that represent request flags.
Acked-by: Song Liu <song@kernel.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20220714180729.1065367-37-bvanassche@acm.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/raid5.c

@@ -1082,7 +1082,8 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
 	should_defer = conf->batch_bio_dispatch && conf->group_cnt;
 
 	for (i = disks; i--; ) {
-		int op, op_flags = 0;
+		enum req_op op;
+		blk_opf_t op_flags = 0;
 		int replace_only = 0;
 		struct bio *bi, *rbi;
 		struct md_rdev *rdev, *rrdev = NULL;