Btrfs: fix access_ok() check in btrfs_ioctl_send()

The closing parenthesis is in the wrong place.  We want to check
"sizeof(*arg->clone_sources) * arg->clone_sources_count" instead of
"sizeof(*arg->clone_sources * arg->clone_sources_count)".

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Jie Liu <jeff.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
cc: stable@vger.kernel.org
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 6837fe8..945d1db 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -4723,8 +4723,8 @@
 	}
 
 	if (!access_ok(VERIFY_READ, arg->clone_sources,
-			sizeof(*arg->clone_sources *
-			arg->clone_sources_count))) {
+			sizeof(*arg->clone_sources) *
+			arg->clone_sources_count)) {
 		ret = -EFAULT;
 		goto out;
 	}