ARM: MediaTek: add basic support for MT8512 boards

This adds a general board file based on MT8512 SoCs from MediaTek.

Apart from the generic parts (cpu) we add some low level init codes
and initialize the early clocks.

This commit is adding the basic boot support for the MT8512 eMMC board.

Signed-off-by: mingming lee <mingming.lee@mediatek.com>
diff --git a/configs/mt8512_bm1_emmc_defconfig b/configs/mt8512_bm1_emmc_defconfig
new file mode 100644
index 0000000..ee3b8e1
--- /dev/null
+++ b/configs/mt8512_bm1_emmc_defconfig
@@ -0,0 +1,44 @@
+CONFIG_ARM=y
+CONFIG_POSITION_INDEPENDENT=y
+CONFIG_ARCH_MEDIATEK=y
+CONFIG_SYS_TEXT_BASE=0x44e00000
+CONFIG_SYS_MALLOC_F_LEN=0x4000
+CONFIG_TARGET_MT8512=y
+CONFIG_SYS_PROMPT="MT8512> "
+CONFIG_NR_DRAM_BANKS=1
+CONFIG_FIT=y
+CONFIG_FIT_SIGNATURE=y
+CONFIG_OF_LIBFDT=y
+# CONFIG_FDT_DEBUG is not set
+CONFIG_LZMA=y
+CONFIG_LZ4=y
+CONFIG_LZO=y
+CONFIG_GZIP=y
+CONFIG_BZIP2=y
+CONFIG_CMD_BOOTMENU=y
+CONFIG_MENU_SHOW=y
+CONFIG_DEFAULT_FDT_FILE="mt8512-bm1-emmc.dtb"
+CONFIG_DEFAULT_DEVICE_TREE="mt8512-bm1-emmc"
+CONFIG_PINCTRL=y
+CONFIG_PINCTRL_MT8512=y
+CONFIG_PINCONF=y
+CONFIG_DM_GPIO=y
+CONFIG_RAM=y
+CONFIG_BAUDRATE=921600
+CONFIG_REGMAP=y
+CONFIG_SYSCON=y
+CONFIG_DM=y
+# CONFIG_DM_DEBUG is not set
+CONFIG_DM_SERIAL=y
+CONFIG_MTK_SERIAL=y
+CONFIG_WDT=y
+CONFIG_WDT_MTK=y
+CONFIG_CLK=y
+CONFIG_TIMER=y
+CONFIG_MTK_TIMER=y
+CONFIG_CMD_MMC=y
+CONFIG_DM_MMC=y
+CONFIG_MMC_MTK=y
+CONFIG_MMC_HS200_SUPPORT=y
+CONFIG_ENV_SIZE=0x1000
+# CONFIG_ENV_IS_IN_MMC is not set