net/sfc: implement representor Rx queue start/stop

net/sfc: implement representor Rx queue start/stop

Add extra libefx flags to Rx queue information initialization
function interface to be able to specify the ingress m-port
flag for a representor RxQ. Rx prefix of packets on that queue
will contain ingress m-port field required for packet forwarding
in representor proxy.

Signed-off-by: Igor Romanov <igor.romanov@oktetlabs.ru>
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Andy Moreton <amoreton@xilinx.com>
Reviewed-by: Ivan Malov <ivan.malov@oktetlabs.ru>