ext4: Move fs/ext4/namei.h into ext4.h

The fs/ext4/namei.h header file had only a single function
declaration, and should have never been a standalone file.  Move it
into ext4.h, where should have been from the beginning.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

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

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

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

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