ext4: drop ext4_handle_dirty_super()

The wrapper is now useless since it does what
ext4_handle_dirty_metadata() does. Just remove it.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201216101844.22917-9-jack@suse.cz


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