btrfs: Remove superfluous check form btrfs_remove_chunk

It's unnecessary to check map->stripes[i].dev for NULL given its value
is already set and dereferenced above the the check. No functional
changes.
Reviewed-by: NQu Wenruo <wqu@suse.com>
Reviewed-by: NAnand Jain <anand.jain@oracle.com>
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/volumes.c

@@ -2848,13 +2848,11 @@ int btrfs_remove_chunk(struct btrfs_trans_handle *trans, u64 chunk_offset)
 			mutex_unlock(&fs_info->chunk_mutex);
 		}
 
-		if (map->stripes[i].dev) {
-			ret = btrfs_update_device(trans, map->stripes[i].dev);
-			if (ret) {
-				mutex_unlock(&fs_devices->device_list_mutex);
-				btrfs_abort_transaction(trans, ret);
-				goto out;
-			}
+		ret = btrfs_update_device(trans, device);
+		if (ret) {
+			mutex_unlock(&fs_devices->device_list_mutex);
+			btrfs_abort_transaction(trans, ret);
+			goto out;
 		}
 	}
 	mutex_unlock(&fs_devices->device_list_mutex);