net: vrf: Add missing Rx counters

The move from rx-handler to L3 receive handler inadvertantly dropped the
rx counters. Restore them.

Fixes: 74b20582 ("net: l3mdev: Add hook in ip and ipv6")
Reported-by: Dinesh Dutt <ddutt@cumulusnetworks.com>
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>