Add CONFIG_BLK_DEV_THROTTLING to check-config.sh

Signed-off-by: Lei Jitang <leijitang@huawei.com>

contrib/check-config.sh

@@ -198,7 +198,7 @@ else
 fi
 
 flags=(
-	BLK_CGROUP IOSCHED_CFQ
+	BLK_CGROUP IOSCHED_CFQ BLK_DEV_THROTTLING
 	CGROUP_PERF
 	CGROUP_HUGETLB
 	NET_CLS_CGROUP $netprio