platform: Move ariane standalone fpga project to its own project

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>

docs/platform/fpga-ariane.md

@@ -0,0 +1,38 @@
+Ariane FPGA SoC Platform
+========================
+Ariane is a 6-stage, single issue, in-order CPU which implements the 64-bit
+RISC-V instruction set. The Ariane FPGA development platform is based on FPGA
+SoC (which currently supports only Genesys 2 board) and is capable of running
+Linux.
+
+The FPGA SoC currently contains the following peripherals:
+- DDR3 memory controller
+- SPI controller to conncet to an SDCard
+- Ethernet controller
+- JTAG port (see debugging section below)
+- Bootrom containing zero stage bootloader and device tree.
+
+To build platform specific library and firmwares, provide the
+*PLATFORM=fpga/ariane* parameter to the top level `make` command.
+
+Platform Options
+----------------
+
+The *Ariane FPGA* platform does not have any platform-specific options.
+
+Building Ariane FPGA Platform
+-----------------------------
+
+**Linux Kernel Payload**
+
+```
+make PLATFORM=fpga/ariane FW_PAYLOAD_PATH=<linux_build_directory>/arch/riscv/boot/Image
+```
+
+Booting Ariane FPGA Platform
+----------------------------
+
+**Linux Kernel Payload**
+
+As Linux kernel image is embedded in the OpenSBI firmware binary, Ariane will
+directly boot into Linux directly after powered on.