enic: Check if hw supports multi wq with vxlan offload

Some adaptors do not support vxlan offload when multi wq is configured.

If hw supports multi wq, BIT(2) is set in a1.

Signed-off-by: Govindarajulu Varadarajan <gvaradar@cisco.com>
Signed-off-by: David S. Miller <davem@davemloft.net>