octeontx2-af: Update/Fix NPC field hash extract feature

1. As per previous implementation, mask and control parameter to
generate the field hash value was not passed to the caller program.
Updated the secret key mbox to share that information as well,
as a part of the fix.
2. Earlier implementation did not consider hash reduction of both
source and destination IPv6 addresses. Only source IPv6 address
was considered. This fix solves that and provides option to hash

Fixes: 56d9f5fd ("octeontx2-af: Use hashed field in MCAM key")
Signed-off-by: Ratheesh Kannoth <rkannoth@marvell.com>
Signed-off-by: Sunil Kovvuri Goutham <sgoutham@marvell.com>
Signed-off-by: Sai Krishna <saikrishnag@marvell.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>