octeontx2-af: Support for changing RSS algorithm

This patch adds support for a RVU PF/VF to change
NIX Rx flowkey algorithm index in NPC RX RSS_ACTION.
eg: a ethtool command changing RSS algorithm for a netdev
interface would trigger this change in NPC.

If PF/VF doesn't specify any MCAM entry index then default
UCAST entry of the NIXLF attached to PF/VF will be updated
with RSS_ACTION and flowkey index.

Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>