dm mpath: use true/false for bool variable

Fixes coccicheck warning:

drivers/md/dm-mpath.c:1447:2-13: WARNING: Assignment of 0/1 to bool variable
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

drivers/md/dm-mpath.c

@@ -1444,7 +1444,7 @@ static void pg_init_done(void *data, int errors)
 		break;
 	case SCSI_DH_RETRY:
 		/* Wait before retrying. */
-		delay_retry = 1;
+		delay_retry = true;
 		/* fall through */
 	case SCSI_DH_IMM_RETRY:
 	case SCSI_DH_RES_TEMP_UNAVAIL: