ARM: dts: STi: Introduce B2260 board

ARM: dts: STi: Introduce B2260 board

B2260 board is the STMicroelectronics 96Board
based on STiH410 soc :
  - 1GB DDR
  - On-Board USB combo WiFi/Bluetooth RTL8723BU
    with PCB soldered antenna
  - Ethernet 1000-BaseT
  - Sata
  - HDMI
  - 2 x USB2 type A
  - micro USB2 type AB
  - SD card slot
  - High speed connector (SD/I2C/USB interfaces)
  - Slow speed connector (UART/I2C/GPIO/SPI/PCM interfaces)

Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Peter Griffin <peter.griffin@linaro.org>