mx6ull_14x14_evk: Add README file

Add a README file to help users getting started with the board.

Signed-off-by: Diego Dorta <diego.dorta@nxp.com>
Reviewed-by: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Jagan Teki <jagan@openedev.com>

board/freescale/mx6ullevk/README

+How to use U-Boot on Freescale MX6ULL 14x14 EVK
+----------------------------------------------
+
+- First make sure you have installed the dtc package (device tree compiler):
+
+$ sudo apt-get install device-tree-compiler
+
+- Build U-Boot for MX6ULL 14x14 EVK:
+
+$ make mrproper
+$ make mx6ull_14x14_evk_defconfig
+$ make
+
+This generates the u-boot-dtb.imx image in the current directory.
+
+- Flash the u-boot-dtb.imx image into the micro SD card:
+
+$ sudo dd if=u-boot-dtb.imx of=/dev/sdb bs=1K seek=1 && sync
+
+- Jumper settings:
+
+SW601: 0 0 1 0
+Sw602: 1 0
+
+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)
+
+Insert the micro SD card in the board, power it up and U-Boot messages should
+come up.
+
+The link for the board: http://www.nxp.com/products/microcontrollers-and- \
+processors/arm-processors/i.mx-applications-processors/i.mx-6-processors/ \
+i.mx6qp/evaluation-kit-for-the-i.mx-6ull-applications-processor:MCIMX6ULL-EVK