octeontx2-pf: Add RSS multi group support

Hardware supports 8 RSS groups per interface. Currently we are using
only group '0'. This patch allows user to create new RSS groups/contexts
and use the same as destination for flow steering rules.

usage:
To steer the traffic to RQ 2,3

ethtool -X eth0 weight 0 0 1 1 context new
(It will print the allocated context id number)
New RSS context is 1

ethtool -N eth0 flow-type tcp4 dst-port 80 context 1 loc 1

To delete the context
ethtool -X eth0 context 1 delete

When an RSS context is removed, the active classification
rules using this context are also removed.

Change-log:

v4
- Fixed compiletime warning.
- Address Saeed's comments on v3.

v3
- Coverted otx2_set_rxfh() to use new function.

v2
- Removed unrelated whitespace
- Coverted otx2_get_rxfh() to use new function.

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