ethtool: Add helper routines to pass vf to rx_flow_spec

ethtool: Add helper routines to pass vf to rx_flow_spec

Orabug: 21669416

The ring_cookie is 64 bits wide which is much larger than can be used
for actual queue index values. So provide some helper routines to
pack a VF index into the cookie. This is useful to steer packets to
a VF ring without having to know the queue layout of the device.

CC: Alex Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
(cherry picked from commit 8cf6f497de405ca9eb87ffb34d90699962d10125)
Signed-off-by: Brian Maly <brian.maly@oracle.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>