The following vector instructions are added from ISA 3.0.

vclzlsbb - Vector Count Leading Zero Least-Significant Bits Byte
vctzlsbb - Vector Count Trailing Zero Least-Significant Bits Byte
Signed-off-by: NRajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>