net: thunderx: add new messages for handle ndo_set_rx_mode callback

The kernel calls ndo_set_rx_mode() callback supplying it will all necessary
info, such as device state flags, multicast mac addresses list and so on.
Since we have only 128 bits to communicate with PF we need to initiate
several requests to PF with small/short operation each based on input data.

So this commit implements following PF messages codes along with new
data structures for them:
NIC_MBOX_MSG_RESET_XCAST to flush all filters configured for this
                          particular network interface (VF)
NIC_MBOX_MSG_ADD_MCAST   to add new MAC address to DMAC filter registers
                          for this particular network interface (VF)
NIC_MBOX_MSG_SET_XCAST   to apply filtering configuration to filter control
                          register

Signed-off-by: Vadim Lomovtsev <Vadim.Lomovtsev@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>