ext4: remove ext4_new_meta_block()

There were only two one callers of the function ext4_new_meta_block(),
which just a very simpler wrapper function around
ext4_new_meta_blocks().  Change those two functions to call
ext4_new_meta_blocks() directly, to save code and stack space usage.

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

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

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

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

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