xfs: remove unnecessary arguments from quota adjust functions

struct xfs_dquot already has a pointer to the xfs mount, so remove the
redundant parameter from xfs_qm_adjust_dq*.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>