mg_disk: fix CONFIG_LBD=y warning

drivers/block/mg_disk.c: In function ‘mg_dump_status’:
drivers/block/mg_disk.c:265: warning: format ‘%ld’ expects type ‘long int’, but
argument 2 has type ‘sector_t’

[ Impact: kill build warning ]

Cc: unsik Kim <donari75@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

drivers/block/mg_disk.c

@@ -79,7 +79,7 @@ static void mg_dump_status(const char *msg, unsigned int stat,
 			if (host->breq) {
 				req = elv_next_request(host->breq);
 				if (req)
-					printk(", sector=%ld", req->sector);
+					printk(", sector=%u", (u32)req->sector);
 			}
 
 		}