When CONFIG_XFS_QUOTA is not defined any quota option is invalid.

Using the macro XFS_IS_QUOTA_RUNNING() as a check if any quota option
has been given is a little misleading so use a simple m_qflags != 0
check to make the intended use more explicit.

Also change to use the IS_ENABLED() macro for the kernel config check.
Signed-off-by: Ian Kent <raven@themaw.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>