arm: imx8m: add support for Advantech RSB-3720

Add initial support for Advantech RSB-3720 board.
The initial support includes:
 - MMC
 - eMMC
 - I2C
 - FEC
 - Serial console

Signed-off-by: Darren Huang <darren.huang@advantech.com.tw>
Signed-off-by: Kevin12.Chen <Kevin12.Chen@advantech.com.tw>
Signed-off-by: Phill.Liu <Phill.Liu@advantech.com.tw>
Signed-off-by: Tim Liang <tim.liang@advantech.com.tw>
Signed-off-by: wei.zeng <wei.zeng@advantech.com.cn>
Signed-off-by: Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
Cc: uboot-imx <uboot-imx@nxp.com>
Cc: Peng Fan (OSS) <peng.fan@oss.nxp.com>
diff --git a/arch/arm/mach-imx/imx8m/Kconfig b/arch/arm/mach-imx/imx8m/Kconfig
index 73bc9b3..cc2975b 100644
--- a/arch/arm/mach-imx/imx8m/Kconfig
+++ b/arch/arm/mach-imx/imx8m/Kconfig
@@ -182,8 +182,23 @@
 	select SUPPORT_SPL
 	select IMX8M_LPDDR4
 	select SUPPORT_EXTENSION_SCAN
+
+config TARGET_IMX8MP_RSB3720A1_4G
+	bool "Support i.MX8MP RSB3720A1 4G"
+	select BINMAN
+	select IMX8MP
+	select SUPPORT_SPL
+	select IMX8M_LPDDR4
+
+config TARGET_IMX8MP_RSB3720A1_6G
+	bool "Support i.MX8MP RSB3720A1 6G"
+	select BINMAN
+	select IMX8MP
+	select SUPPORT_SPL
+	select IMX8M_LPDDR4
 endchoice
 
+source "board/advantech/imx8mp_rsb3720a1/Kconfig"
 source "board/beacon/imx8mm/Kconfig"
 source "board/beacon/imx8mn/Kconfig"
 source "board/compulab/imx8mm-cl-iot-gate/Kconfig"