ARM: dts: am335x: Add Chiliboard DTS

Chiliboard uses ChiliSOM as its base.

Hardware specification:
* ChiliSOM (am335x, PMIC, DRAM, NAND)
* Ethernet PHY (id 0)
* USB host (usb1)
* microSD slot
* 2x GPIO LED

Signed-off-by: Rostislav Lisovy <lisovy@jablotron.cz>
Signed-off-by: Tony Lindgren <tony@atomide.com>