octeontx2-pf: Add support to sync link state between representor and VFs

Implements the below requirement mentioned
in the representors documentation.

"
The representee's link state is controlled through the
representor. Setting the representor administratively UP
or DOWN should cause carrier ON or OFF at the representee.
"

This patch enables
- Reflecting the link state of representor based on the VF state and
 link state of VF based on representor.
- On VF interface up/down a notification is sent via mbox to representor
  to update the link state.
  eg: ip link set eth0 up/down  will disable carrier on/off
       of the corresponding representor(r0p1) interface.
- On representor interface up/down will cause the link state update of VF.
  eg: ip link set r0p1 up/down  will disable carrier on/off
       of the corresponding representee(eth0) interface.

Signed-off-by: Harman Kalra <hkalra@marvell.com>
Signed-off-by: Geetha sowjanya <gakula@marvell.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>