ext4: let ext4_find_entry handle inline data

Create a new function ext4_find_inline_entry() to handle the case of
inline data.

Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

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

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

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