block: make blk_update_request print prefix match ratelimited prefix

In blk_update_request, change the printk_ratelimited
prefix from end_request to blk_update_request so it
matches the name printed if rate limiting occurs.

Old:
[10234.933106] blk_update_request: 174 callbacks suppressed
[10234.934940] end_request: critical target error, dev sdr, sector 16
[10234.949788] end_request: critical target error, dev sdr, sector 16

New:
[16863.445173] blk_update_request: 398 callbacks suppressed
[16863.447029] blk_update_request: critical target error, dev sdr, sector
1442066176
[16863.449383] blk_update_request: critical target error, dev sdr, sector
802802888
[16863.451680] blk_update_request: critical target error, dev sdr, sector
1609535456
Signed-off-by: NRobert Elliott <elliott@hp.com>
Reviewed-by: NWebb Scales <webbnh@hp.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

block/blk-core.c

@@ -2444,8 +2444,8 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
 			error_type = "I/O";
 			break;
 		}
-		printk_ratelimited(KERN_ERR "end_request: %s error, dev %s, sector %llu\n",
-				   error_type, req->rq_disk ?
+		printk_ratelimited(KERN_ERR "%s: %s error, dev %s, sector %llu\n",
+				   __func__, error_type, req->rq_disk ?
 				   req->rq_disk->disk_name : "?",
 				   (unsigned long long)blk_rq_pos(req));