ext4: don't fail remount if journalling mode didn't change

Switching to the new mount api introduced inconsistency in how the
journalling mode mount option (data=) is handled during a remount.

Ext4 always prevented changing the journalling mode during the remount,
however the new code always fails the remount when the journalling mode
is specified, even if it remains unchanged. Fix it.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reported-by: Heiner Kallweit <hkallweit1@gmail.com>
Fixes: cebe85d5 ("ext4: switch to the new mount api")
Link: https://lore.kernel.org/r/20211220152657.101599-1-lczerner@redhat.com


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