nvmet-fc: mark the sqhd field as __le16

That's what it's used as.

Found by sparse.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

drivers/nvme/target/fc.c

@@ -119,7 +119,7 @@ struct nvmet_fc_tgt_queue {
 	u16				qid;
 	u16				sqsize;
 	u16				ersp_ratio;
-	u16				sqhd;
+	__le16				sqhd;
 	int				cpu;
 	atomic_t			connected;
 	atomic_t			sqtail;