bnxt_en: add vf-rep RX/TX and netdev implementation

This patch introduces the RX/TX and a simple netdev implementation
for VF-reps. The VF-reps use the RX/TX rings of the PF. For each VF-rep
the PF driver issues a VFR_ALLOC FW cmd that returns "cfa_code"
and "cfa_action" values. The FW sets up the filter tables in such
a way that VF traffic by default (in absence of other rules)
gets punted to the parent PF. The cfa_code value in the RX-compl
informs the driver of the source VF. For traffic being transmitted
from the VF-rep, the TX BD is tagged with a cfa_action value that
informs the HW to punt it to the corresponding VF.

Signed-off-by: Sathya Perla <sathya.perla@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>