net/enic: support flow API RSS ranges on outer headers

net/enic: support flow API RSS ranges on outer headers

Support rte_flow RSS action on outer headers (level 0). RSS ranges on
the non-default port is OK.
Restrictions:
 - The RETA is ignored. The hash function is simply applied across
   the RSS queue range.
 - The queues used in the RSS group must be sequential.
 - There is a performance hit if the number of queues is not a power
   of 2.

Signed-off-by: John Daley <johndale@cisco.com>
Reviewed-by: Hyong Youb Kim <hyonkim@cisco.com>