meson64: fix Lafrite boot

create new boot script free of G12 stuff, using default u-boot load addresses.
La Frite boots from USB as well as eMMC, add ability to get root device via PARTUUID

config/bootscripts/boot-meson-gx.cmd

@@ -0,0 +1,75 @@
+# DO NOT EDIT THIS FILE
+#
+# Please edit /boot/armbianEnv.txt to set supported parameters
+#
+
+setenv overlay_error "false"
+# default values
+setenv rootdev "/dev/mmcblk1p1"
+setenv verbosity "1"
+setenv console "both"
+setenv bootlogo "false"
+setenv rootfstype "ext4"
+setenv docker_optimizations "on"
+
+# get PARTUUID of first partition on SD/eMMC it was loaded from
+# mmc 0 is always mapped to device u-boot (2016.09+) was loaded from
+if test "${devtype}" = "mmc"; then part uuid mmc ${devnum}:1 partuuid; fi
+if test "${devtype}" = "usb"; then part uuid usb ${devnum}:1 partuuid; fi
+echo "devtype: ${devtype}    ${partuuid}"
+if test "${console}" = "display"; then setenv consoleargs "console=tty1"; fi
+
+	# modern kernel boot
+
+	if test "${console}" = "serial"; then setenv consoleargs "console=ttyAML0,115200"; fi
+	if test "${console}" = "display" || test "${console}" = "both"; then setenv consoleargs "console=ttyAML0,115200 console=tty1"; fi
+	if test "${console}" = "serial"; then setenv consoleargs "console=ttyAML0,115200"; fi
+	if test "${bootlogo}" = "true"; then
+		setenv consoleargs "splash plymouth.ignore-serial-consoles ${consoleargs}"
+	else
+		setenv consoleargs "splash=verbose ${consoleargs}"
+	fi
+	if test "${disable_vu7}" = "false"; then setenv usbhidquirks "usbhid.quirks=0x0eef:0x0005:0x0004"; fi
+
+	setenv bootargs "root=PARTUUID=${partuuid} rootwait rootfstype=${rootfstype} ${consoleargs} consoleblank=0 coherent_pool=2M loglevel=${verbosity} ubootpart=${partuuid} libata.force=noncq usb-storage.quirks=${usbstoragequirks} ${usbhidquirks} ${extraargs} ${extraboardargs}"
+	if test "${docker_optimizations}" = "on"; then setenv bootargs "${bootargs} cgroup_enable=memory swapaccount=1"; fi
+	echo "Mainline bootargs: ${bootargs}"
+
+	load ${devtype} ${devnum} ${ramdisk_addr_r} ${prefix}uInitrd
+	load ${devtype} ${devnum} ${kernel_addr_r} ${prefix}Image
+	load ${devtype} ${devnum} ${fdt_addr_r} ${prefix}dtb/${fdtfile}
+	fdt addr ${fdt_addr_r}
+	fdt resize 65536
+	for overlay_file in ${overlays}; do
+		if load ${devtype} ${devnum} ${scriptaddr} ${prefix}dtb/amlogic/overlay/${overlay_prefix}-${overlay_file}.dtbo; then
+			echo "Applying kernel provided DT overlay ${overlay_prefix}-${overlay_file}.dtbo"
+			fdt apply ${scriptaddr} || setenv overlay_error "true"
+		fi
+	done
+
+	for overlay_file in ${user_overlays}; do
+		if load ${devtype} ${devnum} ${scriptaddr} ${prefix}overlay-user/${overlay_file}.dtbo; then
+			echo "Applying user provided DT overlay ${overlay_file}.dtbo"
+			fdt apply ${scriptaddr} || setenv overlay_error "true"
+		fi
+	done
+
+	if test "${overlay_error}" = "true"; then
+		echo "Error applying DT overlays, restoring original DT"
+		load ${devtype} ${devnum} ${fdt_addr_r} ${prefix}dtb/${fdtfile}
+	else
+		if load ${devtype} ${devnum} ${scriptaddr} ${prefix}dtb/amlogic/overlay/${overlay_prefix}-fixup.scr; then
+			echo "Applying kernel provided DT fixup script (${overlay_prefix}-fixup.scr)"
+			source ${scriptaddr}
+		fi
+		if test -e ${devtype} ${devnum} ${prefix}fixup.scr; then
+			load ${devtype} ${devnum} ${scriptaddr} ${prefix}fixup.scr
+			echo "Applying user provided fixup script (fixup.scr)"
+			source ${scriptaddr}
+		fi
+	fi
+
+	booti ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr_r}
+
+# Recompile with:
+# mkimage -C none -A arm -T script -d /boot/boot.cmd /boot/boot.scr