tg3: Fix NVRAM selftest failures for 5720 devs

This patch fixes NVRAM selftest failures for 5720 devices by fixing the
checksum area size.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tg3.c

@@ -10655,7 +10655,7 @@ error:
 #define NVRAM_SELFBOOT_FORMAT1_3_SIZE	0x1c
 #define NVRAM_SELFBOOT_FORMAT1_4_SIZE	0x20
 #define NVRAM_SELFBOOT_FORMAT1_5_SIZE	0x24
-#define NVRAM_SELFBOOT_FORMAT1_6_SIZE	0x4c
+#define NVRAM_SELFBOOT_FORMAT1_6_SIZE	0x50
 #define NVRAM_SELFBOOT_HW_SIZE 0x20
 #define NVRAM_SELFBOOT_DATA_SIZE 0x1c