vxge: Check if FCS stripping is disabled by the firmware.

- Added a function to check if FCS stripping is disabled by the firmware, if
  it is not disabled fail driver load.

- By default FCS stripping is disabled by the firmware. With this assumption
  driver decrements the indicated packet length by 4 bytes(FCS length).

- This patch ensures that FCS stripping is disabled during driver load time.

Signed-off-by: Sreenivasa Honnur <sreenivasa.honnur@neterion.com>
Signed-off-by: David S. Miller <davem@davemloft.net>