imx: imx8mp_rsb3720a1: convert to DM_SERIAL

Enable CONFIG_DM_SERIAL. uart2 and its pinmux was already
marked with u-boot,dm-spl.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Fabio Estevam <festevam@denx.de>
diff --git a/board/advantech/imx8mp_rsb3720a1/imx8mp_rsb3720a1.c b/board/advantech/imx8mp_rsb3720a1/imx8mp_rsb3720a1.c
index 782025d..f129ebd 100644
--- a/board/advantech/imx8mp_rsb3720a1/imx8mp_rsb3720a1.c
+++ b/board/advantech/imx8mp_rsb3720a1/imx8mp_rsb3720a1.c
@@ -28,14 +28,8 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
-#define UART_PAD_CTRL	(PAD_CTL_DSE6 | PAD_CTL_FSEL1)
 #define WDOG_PAD_CTRL	(PAD_CTL_DSE6 | PAD_CTL_ODE | PAD_CTL_PUE | PAD_CTL_PE)
 
-static const iomux_v3_cfg_t uart_pads[] = {
-	MX8MP_PAD_ECSPI1_SCLK__UART3_DCE_RX | MUX_PAD_CTRL(UART_PAD_CTRL),
-	MX8MP_PAD_ECSPI1_MOSI__UART3_DCE_TX | MUX_PAD_CTRL(UART_PAD_CTRL),
-};
-
 static const iomux_v3_cfg_t wdog_pads[] = {
 	MX8MP_PAD_GPIO1_IO02__WDOG1_WDOG_B  | MUX_PAD_CTRL(WDOG_PAD_CTRL),
 };
@@ -81,8 +75,6 @@
 
 	set_wdog_reset(wdog);
 
-	imx_iomux_v3_setup_multiple_pads(uart_pads, ARRAY_SIZE(uart_pads));
-
 	init_uart_clk(2);
 
 	return 0;
diff --git a/configs/imx8mp_rsb3720a1_4G_defconfig b/configs/imx8mp_rsb3720a1_4G_defconfig
index d7f1aa0..323a7ea 100644
--- a/configs/imx8mp_rsb3720a1_4G_defconfig
+++ b/configs/imx8mp_rsb3720a1_4G_defconfig
@@ -133,6 +133,7 @@
 CONFIG_SPL_DM_REGULATOR_GPIO=y
 CONFIG_DM_RTC=y
 CONFIG_RTC_S35392A=y
+CONFIG_DM_SERIAL=y
 CONFIG_MXC_UART=y
 CONFIG_SPI=y
 CONFIG_DM_SPI=y
diff --git a/configs/imx8mp_rsb3720a1_6G_defconfig b/configs/imx8mp_rsb3720a1_6G_defconfig
index 7ceac2b..3feb639 100644
--- a/configs/imx8mp_rsb3720a1_6G_defconfig
+++ b/configs/imx8mp_rsb3720a1_6G_defconfig
@@ -134,6 +134,7 @@
 CONFIG_SPL_DM_REGULATOR_GPIO=y
 CONFIG_DM_RTC=y
 CONFIG_RTC_S35392A=y
+CONFIG_DM_SERIAL=y
 CONFIG_MXC_UART=y
 CONFIG_SPI=y
 CONFIG_DM_SPI=y
diff --git a/include/configs/imx8mp_rsb3720.h b/include/configs/imx8mp_rsb3720.h
index cd8116f..52e8ea8 100644
--- a/include/configs/imx8mp_rsb3720.h
+++ b/include/configs/imx8mp_rsb3720.h
@@ -168,8 +168,6 @@
 #define PHYS_SDRAM_2_SIZE		0x80000000	/* 2 GB */
 #endif
 
-#define CONFIG_MXC_UART_BASE		UART_BASE_ADDR(3)
-
 /* Monitor Command Prompt */
 #define CONFIG_SYS_CBSIZE		2048
 #define CONFIG_SYS_MAXARGS		64