[PATCH] btrfs: Fix backref.c selftest compilation warning

[Tang Bin <tangbin@xxxxxxxxxxxxxxxxxxxx>]

Fix missing braces compilation warning in the ARM
compiler environment:
    fs/btrfs/backref.c: In function ‘is_shared_data_backref’:
    fs/btrfs/backref.c:394:9: warning: missing braces around initializer [-Wmissing-braces]
      struct prelim_ref target = {0};
    fs/btrfs/backref.c:394:9: warning: (near initialization for ‘target.rbnode’) [-Wmissing-braces]

Signed-off-by: Tang Bin <tangbin@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Shengju Zhang <zhangshengju@xxxxxxxxxxxxxxxxxxxx>
---
 fs/btrfs/backref.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 9c380e7..0cc0257 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -391,7 +391,7 @@ static int is_shared_data_backref(struct preftrees *preftrees, u64 bytenr)
 	struct rb_node **p = &preftrees->direct.root.rb_root.rb_node;
 	struct rb_node *parent = NULL;
 	struct prelim_ref *ref = NULL;
-	struct prelim_ref target = {0};
+	struct prelim_ref target = {};
 	int result;
 
 	target.parent = bytenr;
-- 
2.7.4