xfs: remove various bulk request typedef usage

Remove xfs_bstat_t, xfs_fsop_bulkreq_t, xfs_inogrp_t, and similarly
named compat typedefs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>