ext4: drop sync argument of ext4_commit_super()

Everybody passes 1 as sync argument of ext4_commit_super(). Just drop
it.

Reviewed-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201216101844.22917-3-jack@suse.cz


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