ARM: MediaTek: Add support for MediaTek MT7622 SoC

Add support for MediaTek MT7622 SoC. This include the file
that will initialize the SoC after boot and its device tree.

Signed-off-by: Sam Shih <sam.shih@mediatek.com>
Reviewed-by: Ryder Lee <ryder.lee@mediatek.com>
diff --git a/arch/arm/mach-mediatek/Kconfig b/arch/arm/mach-mediatek/Kconfig
index bca88b8..17b84db 100644
--- a/arch/arm/mach-mediatek/Kconfig
+++ b/arch/arm/mach-mediatek/Kconfig
@@ -13,6 +13,14 @@
 choice
 	prompt "MediaTek board select"
 
+config TARGET_MT7622
+	bool "MediaTek MT7622 SoC"
+	select ARM64
+	help
+	  The MediaTek MT7622 is a ARM64-based SoC with a dual-core Cortex-A53.
+	  including UART, SPI, USB3.0, SD and MMC cards, NAND, SNFI, PWM, PCIe,
+	  Gigabit Ethernet, I2C, built-in Wi-Fi, and PCIe.
+
 config TARGET_MT7623
 	bool "MediaTek MT7623 SoC"
 	select CPU_V7A
@@ -63,6 +71,7 @@
 
 endchoice
 
+source "board/mediatek/mt7622/Kconfig"
 source "board/mediatek/mt7623/Kconfig"
 source "board/mediatek/mt7629/Kconfig"
 source "board/mediatek/mt8512/Kconfig"