arm64: dts: visconti: Add DTS for the VisROBO board

arm64: dts: visconti: Add DTS for the VisROBO board

This board consists of two boards:
the SoM board (VRC SoM) with the SoC on board, and the board for I/O (VRB).

The functions of each board supported by this update are as follows:
  - VRC SoM
    - WDT
    - GPIO
    - SDCard (SPI-MMC mode)
    - I2C x1
  - VRB board
    - VRC SoM
    - UART x2
    - Ethernet phy

Signed-off-by: Yuji Ishikawa <yuji2.ishikawa@toshiba.co.jp>
Link: https://lore.kernel.org/r/20211014092703.15251-4-yuji2.ishikawa@toshiba.co.jp
Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp>