add sunxi/nezha

This is "working", but only to the extent that it boots, works for a while, then hangs :-(

Build here, then
cp cpukernel ~/oreboot/src/mainboard/sunxi/nezha/
cp sun20i-d1-nezha.dtb ~/oreboot/src/mainboard/sunxi/nezha/
cd ~/oreboot/src/mainboard/sunxi/nezha/

PAYLOAD_B=cpukernel PAYLOAD_C=sun20i-d1-nezha.dtb make run

Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>

mainboards/sunxi/nezha/.gitignore

@@ -0,0 +1,5 @@
+cpu.cpio
+cpu.cpio.*
+linux/
+cpukernel
+

mainboards/sunxi/nezha/Makefile

@@ -0,0 +1,53 @@
+# This is the makefile for a cpu kernel and initramfs
+# to be used on a rvboards d1
+#
+# The cpu image uses a cpud as its init, and you
+# can cpu to it to run commands.
+
+default: cpukernel
+
+cpukernel: cpu.cpio.xz cpu.config
+	cp cpu.config linux/.config
+	(cd linux && CROSS_COMPILE=riscv64-linux-gnu- ARCH=riscv make oldconfig && CROSS_COMPILE=riscv64-linux-gnu- ARCH=riscv make -j32)
+	cp linux/arch/riscv/boot/Image cpukernel
+	cp linux/arch/riscv/boot/dts/allwinner/sun20i-d1-nezha.dtb .
+
+# this target builds an initramfs with cpud as init, and the core
+# set of u-root commands.
+# It depends on the kernel setting the IP address.
+# You need ip=dhcp OR ip=fixed.ip.address.here in the command line
+cpu.cpio: Makefile
+	GO111MODULE=off GOARCH=riscv64 CGO_ENABLED=0 u-root -o cpu.cpio -build=bb -files ~/.ssh/cpu_rsa.pub:key.pub \
+		core \
+		github.com/u-root/cpu/cmds/cpud
+
+cpu.cpio.xz: cpu.cpio
+	xz --check=crc32 -9 --lzma2=dict=1MiB --stdout cpu.cpio | dd conv=sync bs=512 of=cpu.cpio.xz
+
+# These stanzas fetch code.
+fetch: getkernel geturoot
+
+getkernel:
+	rm -rf linux
+	git clone --depth=1 -b v5.15.5-openwrt --single-branch https://github.com/orangecms/linux
+
+geturoot:
+	GO111MODULE=off go get -u github.com/u-root/u-root
+	GO111MODULE=off go get -u github.com/u-root/cpu/...
+
+# Serve the combined sshd-kernel and sshd-initramfs image. This includes flashrom
+sshd-pxeserver:
+	echo Consider Disabling any system services ...
+	echo e.g. sudo systemctl  stop tftpd-hpa.service
+	echo e.g. sudo systemctl stop isc-dhcp-server
+	sudo `go env GOPATH`/bin/pxeserver  -tftp-dir . -bootfilename sshdkernel  -http-dir . -interface $(NETWORK)
+
+# Serve the combined cpu-kernel and cpu-initramfs image.
+cpu-pxeserver:
+	echo Consider Disabling any system services ...
+	echo e.g. sudo systemctl  stop tftpd-hpa.service
+	echo e.g. sudo systemctl stop isc-dhcp-server
+	sudo `go env GOPATH`/bin/pxeserver  -tftp-dir . -bootfilename cpukernel  -http-dir . -interface $(NETWORK)
+
+ssh:
+	ssh -i class_key -p 2022 root@up