tg3: Add Macronix NVRAM support

This patch adds the support for Macronix NVRAM

Signed-off-by: Prashant Sreedharan <prashant.sreedharan@broadcom.com>
Signed-off-by: Satish Baddipadige <satish.baddipadige@broadcom.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>