scsi: qla4xxx: Fix inconsistent format argument type

Fix the following warning:

[drivers/scsi/qla4xxx/ql4_nx.c:3228]: (warning) %ld in format string (no. 1)
	requires 'long' but the argument type is 'unsigned long'.

Link: https://lore.kernel.org/r/20200930022228.2840587-1-yebin10@huawei.com
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Ye Bin <yebin10@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: Ye Bin

drivers/scsi/qla4xxx/ql4_nx.c

@@ -3226,7 +3226,7 @@ static void qla4_8xxx_uevent_emit(struct scsi_qla_host *ha, u32 code)
 
 	switch (code) {
 	case QL4_UEVENT_CODE_FW_DUMP:
-		snprintf(event_string, sizeof(event_string), "FW_DUMP=%ld",
+		snprintf(event_string, sizeof(event_string), "FW_DUMP=%lu",
 			 ha->host_no);
 		break;
 	default: