btrfs: Cleanup some redundant codes in btrfs_lookup_csums_range()

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index bc3c924..ad3cd86 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -358,11 +358,8 @@
 
 		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 		if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID ||
-		    key.type != BTRFS_EXTENT_CSUM_KEY)
-			break;
-
-		btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
-		if (key.offset > end)
+		    key.type != BTRFS_EXTENT_CSUM_KEY ||
+		    key.offset > end)
 			break;
 
 		if (key.offset > start)