sunxi: Convert CONFIG_SATAPWR to Kconfig

Convert the CONFIG_SATAPWR into kconfig.
Thanks to that, many SYS_EXTRA_OPTIONS can be removed from some
defconfigs.

Signed-off-by: Mylène Josserand <mylene.josserand@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
diff --git a/configs/A20-Olimex-SOM-EVB_defconfig b/configs/A20-Olimex-SOM-EVB_defconfig
index ce658ca..6c87648 100644
--- a/configs/A20-Olimex-SOM-EVB_defconfig
+++ b/configs/A20-Olimex-SOM-EVB_defconfig
@@ -8,10 +8,10 @@
 CONFIG_MMC_SUNXI_SLOT_EXTRA=3
 CONFIG_USB0_VBUS_PIN="PB9"
 CONFIG_USB0_VBUS_DET="PH5"
+CONFIG_SATAPWR="PC3"
 CONFIG_DEFAULT_DEVICE_TREE="sun7i-a20-olimex-som-evb"
 CONFIG_AHCI=y
 # CONFIG_SYS_MALLOC_CLEAR_ON_INIT is not set
-CONFIG_SYS_EXTRA_OPTIONS="SATAPWR=SUNXI_GPC(3)"
 CONFIG_SPL=y
 CONFIG_SPL_I2C_SUPPORT=y
 # CONFIG_CMD_IMLS is not set