octeontx2-pf: Fix algorithm index in MCAM rules with RSS action

Otherthan setting action as RSS in NPC MCAM entry, RSS flowkey
algorithm index also needs to be set. Otherwise whatever algorithm
is defined at flowkey index '0' will be considered by HW and pkt
flows will be distributed as such.

Fix this by saving the flowkey index sent by admin function while
initializing RSS and then use it when framing MCAM rules.

Fixes: 81a43620

 ("octeontx2-pf: Add RSS multi group support")
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>