When preventing DAX and journaling on an inode.  Use the effective DAX
check rather than the mount option.

This will be required to support per inode DAX flags.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20200528150003.828793-2-ira.weiny@intel.comSigned-off-by: Theodore Ts'o <tytso@mit.edu>