ext4: let ext4_group_add_blocks() return an error code

This patch lets ext4_group_add_blocks() return an error code if it
fails, so that upper functions can handle error correctly.

Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --cc fs/ext4/ext4.h
Simple merge

diff --cc fs/ext4/mballoc.c
Simple merge

diff --cc fs/ext4/resize.c
Simple merge