xfs: bump XFS_IOC_FSGEOMETRY to v5 structures

Unfortunately, the V4 XFS_IOC_FSGEOMETRY structure is out of space so we
can't just add a new field to it. Hence we need to bump the definition
to V5 and and treat the V4 ioctl and structure similar to v1 to v3.

While doing this, clean up all the definitions associated with the
XFS_IOC_FSGEOMETRY ioctl.

Signed-Off-By: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: forward port to 5.1, expand structure size to 256 bytes]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
