configs: am335x_evm: Support GbE PHYs

The SanCloud BeagleBone Enhanced (BBE) includes a Gigabit Ethernet PHY.

Signed-off-by: Paul Barker <paul.barker@sancloud.com>
diff --git a/configs/am335x_evm_defconfig b/configs/am335x_evm_defconfig
index 85a4206..0315fa6 100644
--- a/configs/am335x_evm_defconfig
+++ b/configs/am335x_evm_defconfig
@@ -67,6 +67,7 @@
 CONFIG_PHY_ATHEROS=y
 CONFIG_PHY_SMSC=y
 CONFIG_DM_ETH=y
+CONFIG_PHY_GIGE=y
 CONFIG_MII=y
 CONFIG_DRIVER_TI_CPSW=y
 CONFIG_SPI=y