xfs: Add support for the Q_XGETQSTATV

For XFS, add support for Q_XGETQSTATV quotactl command.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Reviewed-by: Rich Johnston <rjohnston@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>