sfc: add support for devlink port_function_hw_addr_get in ef100

Using the builtin client handle id infrastructure, add support for
obtaining the mac address linked to mports in ef100. This implies
to execute an MCDI command for getting the data from the firmware
for each devlink port.

Signed-off-by: Alejandro Lucero <alejandro.lucero-palau@amd.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Acked-by: Martin Habets <habetsm.xilinx@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>