Ext3: use unlikely to improve the efficiency of the kernel

Because the function 'sb_getblk' seldomly fails to return
NULL value,it will be better to use unlikely to check it.

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --cc fs/ext3/inode.c
Simple merge

diff --cc fs/ext3/resize.c
Simple merge

diff --cc fs/ext3/xattr.c
Simple merge