btrfs: ref-verify: Remove unused parameter from walk_up_tree() to kill warning

With gcc-4.1.2:

    fs/btrfs/ref-verify.c: In function ‘btrfs_build_ref_tree’:
    fs/btrfs/ref-verify.c:1017: warning: ‘root’ is used uninitialized in this function

The variable is indeed passed uninitialized, but it is never used by the
callee.  However, not all versions of gcc are smart enough to notice.

Hence remove the unused parameter from walk_up_tree() to silence the
compiler warning.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c
index 3487869..171f3cc 100644
--- a/fs/btrfs/ref-verify.c
+++ b/fs/btrfs/ref-verify.c
@@ -606,8 +606,7 @@
 }
 
 /* Walk up to the next node that needs to be processed */
-static int walk_up_tree(struct btrfs_root *root, struct btrfs_path *path,
-			int *level)
+static int walk_up_tree(struct btrfs_path *path, int *level)
 {
 	int l;
 
@@ -984,7 +983,6 @@
 int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info)
 {
 	struct btrfs_path *path;
-	struct btrfs_root *root;
 	struct extent_buffer *eb;
 	u64 bytenr = 0, num_bytes = 0;
 	int ret, level;
@@ -1014,7 +1012,7 @@
 				     &bytenr, &num_bytes);
 		if (ret)
 			break;
-		ret = walk_up_tree(root, path, &level);
+		ret = walk_up_tree(path, &level);
 		if (ret < 0)
 			break;
 		if (ret > 0) {