o introduce a flags 'errata' for HW bugs onto the softc.
o remove errata_a0 and introduce the corresponding flags into 'errata'.
o introduce a new errata for K8, namely some platform might set the
PENDING_BIT but aren't able to unset it, also don't loop forever
waiting PENDING_BIT being cleared.
o try to introduce a workaround for the PENDING_BIT stuck problem,
o support now half multipliers for K8.