net: ti: icssg: Add support sending FDB command to update rx_flow_id

ICSSG firmware supports FDB commands. Add support to send FDB commands
from driver. Once rx_flow_id is obtained from dma, let firmware know that
we are using this rx_flow_id by sending a FDB command.

Reviewed-by: Ravi Gunasekaran <r-gunasekaran@ti.com>
Signed-off-by: MD Danish Anwar <danishanwar@ti.com>