ARM: dts: Add support for the cpuimx51 board from Eukrea and its baseboard.

ARM: dts: Add support for the cpuimx51 board from Eukrea and its baseboard.

The following devices/functionalities were added:
 * Main and secondary UARTs.
 * i2c and the pcf8563 device.
 * Ethernet.
 * NAND.
 * The BP1 button.
 * The LED.
 * Watchdog
 * SD.

Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: devicetree@vger.kernel.org
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Eric Bénard <eric@eukrea.com>
Signed-off-by: Denis Carikli <denis@eukrea.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>