xfs: remove the dsunit and dswidth variables in

There is no real need for the local variables here - either they
are applied to the mount structure, or if the noalign mount option
is set the mount will fail entirely if either is set.  Removing
them helps cleaning up the mount API conversion.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>