mmc: core: Fix blk_status_t handling

Sparse spits out this following warning:

drivers/mmc/core/queue.c:311:21: warning: incorrect type in assignment (different base types)
drivers/mmc/core/queue.c:311:21:    expected int ret
drivers/mmc/core/queue.c:311:21:    got restricted blk_status_t [usertype]
drivers/mmc/core/queue.c:314:21: warning: incorrect type in assignment (different base types)
drivers/mmc/core/queue.c:314:21:    expected int ret
drivers/mmc/core/queue.c:314:21:    got restricted blk_status_t [usertype]
drivers/mmc/core/queue.c:336:16: warning: incorrect type in return expression (different base types)
drivers/mmc/core/queue.c:336:16:    expected restricted blk_status_t
drivers/mmc/core/queue.c:336:16:    got int [assigned] ret

ret is only used for blk_status_t types, so make it that type.
Signed-off-by: NJoel Stanley <joel@jms.id.au>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211215011336.194089-1-joel@jms.id.auSigned-off-by: NUlf Hansson <ulf.hansson@linaro.org>

drivers/mmc/core/queue.c

@@ -234,7 +234,7 @@ static blk_status_t mmc_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
 	enum mmc_issue_type issue_type;
 	enum mmc_issued issued;
 	bool get_card, cqe_retune_ok;
-	int ret;
+	blk_status_t ret;
 
 	if (mmc_card_removed(mq->card)) {
 		req->rq_flags |= RQF_QUIET;