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: NJohn Fastabend <john.r.fastabend@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>