add device milkv-duo256m-glibc-arm64-sd

Signed-off-by: carbon <carbon@milkv.io>

device/milkv-duo256m-glibc-arm64-sd/boardconfig.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+export MV_BOARD=milkv-duo256m-glibc-arm64-sd
+export MV_VENDOR=milkv
+export MV_BUILD_ENV=envsetup_milkv.sh
+export MV_BOARD_LINK=sg2002_milkv_duo256m_glibc_arm64_sd
+

device/milkv-duo256m-glibc-arm64-sd/genimage.cfg

@@ -0,0 +1,33 @@
+image boot.vfat {
+	vfat {
+		label = "boot"
+		files = {
+			"fip.bin",
+			"rawimages/boot.sd",
+		}
+	}
+	size = 128M
+}
+
+image rootfs.ext4 {
+	ext4 {
+		label = "rootfs"
+	}
+	size = 768M
+}
+
+image milkv-duo256m-glibc-arm64-sd.img {
+	hdimage {
+	}
+
+	partition boot {
+		partition-type = 0xC
+		bootable = "true"
+                image = "boot.vfat"
+	}
+
+	partition rootfs {
+		partition-type = 0x83
+		image = "rootfs.ext4"
+	}
+}