block: Relocate BLK_MQ_MAX_DEPTH

BLK_MQ_MAX_DEPTH is defined as an enumerated value, but has no real
relation to the other members in its enum, so just use #define to provide
the definition.
Signed-off-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20240719112912.3830443-7-john.g.garry@oracle.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

include/linux/blk-mq.h

@@ -670,8 +670,6 @@ enum {
 
 	/* hw queue is inactive after all its CPUs become offline */
 	BLK_MQ_S_INACTIVE	= 3,
-
-	BLK_MQ_MAX_DEPTH	= 10240,
 };
 #define BLK_MQ_FLAG_TO_ALLOC_POLICY(flags) \
 	((flags >> BLK_MQ_F_ALLOC_POLICY_START_BIT) & \
@@ -680,6 +678,7 @@ enum {
 	((policy & ((1 << BLK_MQ_F_ALLOC_POLICY_BITS) - 1)) \
 		<< BLK_MQ_F_ALLOC_POLICY_START_BIT)
 
+#define BLK_MQ_MAX_DEPTH	(10240)
 #define BLK_MQ_NO_HCTX_IDX	(-1U)
 
 struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set,