sunxi: Move SUNXI_GMAC to Kconfig

Move the SUNXI_GMAC config option to Kconfig, remove it
from SYS_EXTRA_OPTIONS and rename it into SUN7I_GMAC.

Signed-off-by: Mylène Josserand <mylene.josserand@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
diff --git a/configs/Cubietruck_defconfig b/configs/Cubietruck_defconfig
index ca549bc..576ccc3 100644
--- a/configs/Cubietruck_defconfig
+++ b/configs/Cubietruck_defconfig
@@ -11,7 +11,7 @@
 CONFIG_DEFAULT_DEVICE_TREE="sun7i-a20-cubietruck"
 CONFIG_AHCI=y
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
-CONFIG_SYS_EXTRA_OPTIONS="SUNXI_GMAC,RGMII,SATAPWR=SUNXI_GPH(12)"
+CONFIG_SYS_EXTRA_OPTIONS="RGMII,SATAPWR=SUNXI_GPH(12)"
 CONFIG_SPL=y
 CONFIG_SPL_I2C_SUPPORT=y
 # CONFIG_CMD_IMLS is not set
@@ -24,6 +24,7 @@
 # CONFIG_SPL_PARTITION_UUIDS is not set
 CONFIG_DFU_RAM=y
 CONFIG_ETH_DESIGNWARE=y
+CONFIG_SUN7I_GMAC=y
 CONFIG_USB_EHCI_HCD=y
 CONFIG_USB_MUSB_GADGET=y
 CONFIG_USB_GADGET=y