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/icnova-a20-swac_defconfig b/configs/icnova-a20-swac_defconfig
index 30e75e3..569f2d9 100644
--- a/configs/icnova-a20-swac_defconfig
+++ b/configs/icnova-a20-swac_defconfig
@@ -12,7 +12,7 @@
 CONFIG_VIDEO_LCD_PANEL_LVDS=y
 CONFIG_DEFAULT_DEVICE_TREE="sun7i-a20-icnova-swac"
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
-CONFIG_SYS_EXTRA_OPTIONS="AXP209_POWER,SUNXI_GMAC,CMD_BMP"
+CONFIG_SYS_EXTRA_OPTIONS="AXP209_POWER,CMD_BMP"
 CONFIG_SPL=y
 CONFIG_SPL_I2C_SUPPORT=y
 # CONFIG_CMD_IMLS is not set
@@ -23,4 +23,5 @@
 # CONFIG_SPL_ISO_PARTITION is not set
 # CONFIG_SPL_EFI_PARTITION is not set
 CONFIG_ETH_DESIGNWARE=y
+CONFIG_SUN7I_GMAC=y
 CONFIG_USB_EHCI_HCD=y