ARM: dts: sun8i-a33: Add dts for Sinlinx SinA33 development board.

The SinA33 is a core/SDK development board by Sinlinx. The core board
does not have any connectors or pads, other than the pads used to connect
it to the SDK board.

The core board only has the A33 SoC, 2 RAM chips, an eMMC flash chip,
the AXP223 PMIC, and supporting discrete components. eMMC is optional.

The SDK board has a USB host, USB OTG, volume control and home buttons,
audio input/output jacks, a micro-SD slot, camera and SDIO expansion
headers, an LCD connector, and a GPIO expansion header, which has
UARTs, MIPI DSI and I2C available. Only UART0 is enabled though.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>