include/net.h: add max_speed member in struct eth_pdata

This will be used for getting max speed mode of Ethernet interface that
a particular MAC supports from Device Tree blob and later being used for
phy configuration.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Joe Hershberger <joe.hershberger@ni.com>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>

include/net.h

@@ -86,11 +86,13 @@ enum eth_state_t {
  * @iobase: The base address of the hardware registers
  * @enetaddr: The Ethernet MAC address that is loaded from EEPROM or env
  * @phy_interface: PHY interface to use - see PHY_INTERFACE_MODE_...
+ * @max_speed: Maximum speed of Ethernet connection supported by MAC
  */
 struct eth_pdata {
 	phys_addr_t iobase;
 	unsigned char enetaddr[6];
 	int phy_interface;
+	int max_speed;
 };
 
 enum eth_recv_flags {