net: pch_gbe: Add Kconfig option

Add Kconfig option in preparation for moving board to use Kconfig.
Signed-off-by: NBin Meng <bmeng.cn@gmail.com>

drivers/net/Kconfig

@@ -8,6 +8,11 @@ config DM_ETH
 	  This is currently implemented in net/eth.c
 	  Look in include/net.h for details.
 
+config PHYLIB
+	bool "Ethernet PHY (physical media interface) support"
+	help
+	  Enable Ethernet PHY (physical media interface) support.
+
 menuconfig NETDEVICES
 	bool "Network device support"
 	depends on NET
@@ -79,4 +84,12 @@ config ETH_DESIGNWARE
 	  100Mbit and 1 Gbit operation. You must enable CONFIG_PHYLIB to
 	  provide the PHY (physical media interface).
 
+config PCH_GBE
+	bool "Intel Platform Controller Hub EG20T GMAC driver"
+	depends on DM_ETH && DM_PCI
+	select PHYLIB
+	help
+	  This MAC is present in Intel Platform Controller Hub EG20T. It
+	  supports 10/100/1000 Mbps operation.
+
 endif # NETDEVICES