doc: board: Convert i.MX6UL 14x14 EVK README to reST

Convert plain text documentation to reStructuredText format and add
it to Sphinx TOC tree. No essential content change.

Signed-off-by: Peng Fan <peng.fan@nxp.com>

doc/board/freescale/index.rst

@@ -16,3 +16,4 @@ Freescale
    imxrt1050-evk
    mx6sabreauto
    mx6sabresd
+   mx6ul_14x14_evk

doc/board/freescale/mx6ul_14x14_evk.rst

@@ -1,8 +1,15 @@
+.. SPDX-License-Identifier: GPL-2.0+
+
+mx6ul_14x14_evk
+===============
+
 How to use U-Boot on Freescale MX6UL 14x14 EVK
 -----------------------------------------------
 
 - Build U-Boot for MX6UL 14x14 EVK:
 
+.. code-block:: bash
+
    $ make mrproper
    $ make mx6ul_14x14_evk_defconfig
    $ make
@@ -14,13 +21,17 @@ This will generate the SPL image called SPL and the u-boot.img.
 
 - Flash the SPL image into the micro SD card:
 
+.. code-block:: bash
+
    sudo dd if=SPL of=/dev/mmcblk0 bs=1k seek=1 conv=notrunc; sync
 
 - Flash the u-boot.img image into the micro SD card:
 
+.. code-block:: bash
+
    sudo dd if=u-boot.img of=/dev/mmcblk0 bs=1k seek=69 conv=notrunc; sync
 
-- Jumper settings:
+- Jumper settings::
 
    SW601: 0 0 1 0
    Sw602: 1 0
@@ -29,17 +40,16 @@ where 0 means bottom position and 1 means top position (from the
 switch label numbers reference).
 
 - Connect the USB cable between the EVK and the PC for the console.
-(The USB console connector is the one close the push buttons)
+  The USB console connector is the one close the push buttons
 
-- Insert the micro SD card in the board, power it up and U-Boot messages should
+- Insert the micro SD card in the board, power it up and U-Boot messages should come up.
-come up.
 
 2. Booting via Serial Download Protocol (SDP)
 ---------------------------------------------
 
 The mx6ulevk board can boot from USB OTG port using the SDP, target will
 enter in SDP mode in case an SD Card is not connect or boot switches are
-set as below:
+set as below::
 
    Sw602: 0 1
    SW601: x x x x
@@ -54,6 +64,8 @@ https://github.com/NXPmicro/mfgtools
 
 The following script should be created to boot SPL + u-boot-dtb.img binaries:
 
+.. code-block:: bash
+
    $ cat uuu_script
      uuu_version 1.1.4
 
@@ -68,6 +80,8 @@ Please note that the address above is calculated based on SYS_TEXT_BASE address:
 
 Power on the target and run the following command from U-Boot root directory:
 
+.. code-block:: bash
+
    $ sudo ./uuu uuu_script
 
 - Method 2: imx usb loader tool (imx_usb):
@@ -78,5 +92,7 @@ https://github.com/boundarydevices/imx_usb_loader
 Build the source code and run the following commands from U-Boot root
 directory:
 
+.. code-block:: bash
+
    $ sudo ./imx_usb SPL
    $ sudo ./imx_usb u-boot-dtb.img