ext4: clean up ext4_abort() so __func__ is now implicit

Use a macro definition for ext4_abort() to clean up the .c files a wee
bit.

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

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

diff --cc fs/ext4/ext4_jbd2.c
Simple merge

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