xfs: standardize quota verification function outputs

xfs: standardize quota verification function outputs

Rename xfs_dqcheck to xfs_dquot_verify and make it return an
xfs_failaddr_t like every other structure verifier function.
This enables us to check on-disk quotas in the same way that we check
everything else.  Callers are now responsible for logging errors, as
XFS_QMOPT_DOWARN goes away.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>