doc: fix board/openpiton/riscv64.rst

* remove duplicate heading to avoid build error with 'make htmldocs'
* length of underlines must match header
* use appropriate header levels
* fix type %s/linux/Linux/
Signed-off-by: NHeinrich Schuchardt <xypron.glpk@gmx.de>

doc/board/openpiton/riscv64.rst

@@ -3,8 +3,6 @@
 Openpiton RISC-V SoC
 ====================
 
-OpenPiton RISC-V SoC
---------------------
 OpenPiton is an open source, manycore processor and research platform. It is a
 tiled manycore framework scalable from one to 1/2 billion cores. It supports a
 number of ISAs including RISC-V with its P-Mesh cache coherence protocol and
@@ -14,21 +12,23 @@ running full-stack Debian linux.
 
 RISC-V Standard Bootflow
 -------------------------
+
 Currently, OpenPiton implements RISC-V standard bootflow in the following steps
 mover.S -> u-boot-spl -> opensbi -> u-boot -> Linux
 This board supports S-mode u-boot as well as M-mode SPL
 
 Building OpenPition
 ---------------------
+
 If you'd like to build OpenPiton, please go to OpenPiton github repo
 (at https://github.com/PrincetonUniversity/openpiton) to build from the latest
 changes
 
 Building Images
----------------------------
+---------------
 
 SPL
----
+~~~
 
 1. Add the RISC-V toolchain to your PATH.
 2. Setup ARCH & cross compilation environment variable:
@@ -42,7 +42,7 @@ SPL
 4. make
 
 U-Boot
-------
+~~~~~~
 
 1. Add the RISC-V toolchain to your PATH.
 2. Setup ARCH & cross compilation environment variable:
@@ -55,9 +55,8 @@ U-Boot
 3. make openpiton_riscv64_defconfig
 4. make
 
-
 opensbi
--------
+~~~~~~~
 
 1. Add the RISC-V toolchain to your PATH.
 2. Setup ARCH & cross compilation environment variable:
@@ -70,9 +69,9 @@ opensbi
 3. Go to OpenSBI directory
 4. make PLATFORM=fpga/openpiton FW_PAYLOAD_PATH=<path to u-boot-nodtb.bin>
 
+Using fw_payload.bin with Linux
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-Using fw_payload.bin with linux
--------------------------------
 Put the generated fw_payload.bin into the /boot directory on the root filesystem,
 plug in the SD card, then flash the bitstream. Linux will boot automatically.
 
@@ -81,7 +80,7 @@ Booting
 Once you plugin the sdcard and power up, you should see the U-Boot prompt.
 
 Sample Dual-core Debian boot log from OpenPiton
------------------------------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 .. code-block:: none