be2net: query FW to check if EVB is enabled

The current code assumes that bridge functionality (EVB) in the adapter
is enabled only when SR-IOV is enabled. This is not always true.
This patch uses the GET_HSW_CONFIG FW cmd to query this from the FW.

Signed-off-by: Kalesh AP <kalesh.purayil@avagotech.com>
Signed-off-by: Sathya Perla <sathya.perla@avagotech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>