cxgb4vf: FL Starvation Threshold needs to be larger than the SGE's Egress Congestion Threshold

Free List Starvation Threshold needs to be larger than the SGE's Egress
Congestion Threshold or we'll end up in a mutual stall where the driver waits
for Ingress Packets to drive replacing Free List Pointers and the SGE waits for
Free List Pointers before pushing Ingress Packets to the host.

Based on original work by Casey Leedom <leedom@chelsio.com>

Signed-off-by: Hariprasad Shenai <hariprasad@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>