rockchip: vamrs: rock960: Migrate to use IO-domain driver

Switch to use the IO-domain driver to configure IO-domain based on
device tree instead of a setup_iodomain() function.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/configs/rock960-rk3399_defconfig b/configs/rock960-rk3399_defconfig
index 5c0b95f..13575c5 100644
--- a/configs/rock960-rk3399_defconfig
+++ b/configs/rock960-rk3399_defconfig
@@ -39,6 +39,7 @@
 CONFIG_SYS_MMC_ENV_DEV=1
 CONFIG_ROCKCHIP_GPIO=y
 CONFIG_SYS_I2C_ROCKCHIP=y
+CONFIG_ROCKCHIP_IODOMAIN=y
 CONFIG_MMC_DW=y
 CONFIG_MMC_DW_ROCKCHIP=y
 CONFIG_MMC_SDHCI=y