tg3: add support for Ethernet core in bcm4785

The BCM4785 or sometimes named BMC4705 is a Broadcom SoC which a
Gigabit 5750 Ethernet core. The core is connected via PCI with the rest
of the SoC, but it uses some extension.

This core does not use a firmware or an eeprom.

Some devices only have a switch which supports 100MBit/s, this
currently does not work with this driver.

This patch was original written by Michael Buesch <[email protected]> and is in
OpenWrt for some years now.

This was tested on a Linksys WRT610N V1 and older versions of this patch
were tested by other people on different devices.

Signed-off-by: Hauke Mehrtens <[email protected]>
Acked-by: Michael Chan <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
index 0eb6579..907e7e5 100644
--- a/include/linux/pci_ids.h
+++ b/include/linux/pci_ids.h
@@ -2127,6 +2127,7 @@
 #define PCI_DEVICE_ID_TIGON3_5754M	0x1672
 #define PCI_DEVICE_ID_TIGON3_5755M	0x1673
 #define PCI_DEVICE_ID_TIGON3_5756	0x1674
+#define PCI_DEVICE_ID_TIGON3_5750	0x1676
 #define PCI_DEVICE_ID_TIGON3_5751	0x1677
 #define PCI_DEVICE_ID_TIGON3_5715	0x1678
 #define PCI_DEVICE_ID_TIGON3_5715S	0x1679