ARM: dts: add support to DB600c

This patch adds support to DB600c P1 board, which is subjected to
change.

Here is the list of things tested on this board and know issues.

Tested:
-------------------

1> UART: Only DEBUG uart has been tested.

2> 2 USB ports on the board are tested with USB stick.

3> PCIE  and ETHERNET, Tested with Wired Ethernet on board.

4>  LEDs: Heart beat LED seems to work fine.

5> eMMC: tested with rootfs.

6> HDMI: Tested with FB console.

Hardware issues:
-------------------

1> I2C: 2 instances of GSBIs are wired up with 2 I2C instances on each
of them. which seems to be a issue because each gsbi has only one I2C
instance.

2> SATA: There seems to be issue with both andriod and Linux kernels to
detect few types of disks, this issue needs more understanding by
looking a sata eye-diagram

NOT Tested:
-------------------
1> SPI@

2> All the LEDS

3> SD CARD: SD card on linux seems to not work, Am debugging this issue,
it could a software issue.

4> WLAN: Not tested as its subjected to change.

5> AUDIO: Not tested, will test digital audio in next week. Analog audio
has dependency on Sagar's Slim Bus Patches.

6> Debian Desktop: There seems to be a issue with Splash screen enabled
bootloaders. When we try to bringup the display it goes blue, however
same software works fine on IFC6410. Am guessing that this could be
issue due to clks handover from bootloader to linux w.r.t display.

7> SAW Regulators: Looks like there is an issue if we attempt to enable
SAW regualtors, I have not spend much time to look at this issue, but I
will start debugging this very soon.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>