I suppose the real solution is having userspace do some "bridge mdb add"
yoga, but since no code currently uses
MV88E6XXX_G1_ATU_DATA_STATE_MC_STATIC_DA_MGMT, I don't think there's any
way to actually achieve this. And I have no idea how to represent the
requirement that "frames with this multicast DA are only to be directed
at the CPU" in a hardware-agnostic way.

The switchdev interface for this exists, because there can be
multicast listeners on the bridge. When they join a group, they ask
the switch to put in a HOST MDB, which should cause the traffic for
the group to be sent to the host. What you don't have is the
exclusivity. If there is an IGMP report for the DA received on another
port, IGMP snooping will add an MDB entry to forward traffic out that
port.

	Andrew