tg3: Handle NVRAM absent cases

Some 57780 ASIC revision parts do not have NVRAM.  Code the driver so
that it is tolerant of this configuration.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/tg3.h b/drivers/net/tg3.h
index ca71a49..afbabf2 100644
--- a/drivers/net/tg3.h
+++ b/drivers/net/tg3.h
@@ -2636,6 +2636,7 @@
 #define TG3_FLG3_CLKREQ_BUG		0x00000800
 #define TG3_FLG3_PHY_ENABLE_APD		0x00001000
 #define TG3_FLG3_5755_PLUS		0x00002000
+#define TG3_FLG3_NO_NVRAM		0x00004000
 
 	struct timer_list		timer;
 	u16				timer_counter;