ext4: allow the dax flag to be set and cleared on inline directories

commit 4811d992 upstream.

This is needed to allow generic/607 to pass for file systems with the
inline data_feature enabled, and it allows the use of file systems
where the directories use inline_data, while the files are accessed
via DAX.

Cc: stable@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>