ARM: dts: rockchip: Add support for PCM-947 carrier board

Add basic support for the PCM-947 carrier board, a RK3288 based development
board made by PHYTEC. This board works in a combination with
the phyCORE-RK3288 System on Module.

Following interfaces and devices are available on the PCM-947 carrier board:

  - 2x UART
  - micro SDMMC
  - USB host and USB otg
  - USB 3503 HSIC hub
  - Ethernet
  - 2nd alternative KSZ9031 ethernet phy
  - Display connectors: PHYTEC LVDS, DDG LVDS, parallel signals, HDMI
  - Parallel Camera CIF
  - SGTL5000-32QFN audio codec
  - 4x LEDs connected via PCA9533
  - 2 user buttons
  - Expansion connectors for WiFi and other modules
  - RTC RV-4162-C7
  - Resistive touch STMPE811
  - EEPROM M24C32

Signed-off-by: Wadim Egorov <w.egorov@phytec.de>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>