ARM: cfa10036: dt: Change i2c0 clock frequency

The OLED display can work faster. Change the i2c controller clock
frequency to remove the tearing effect that can be seen on the display.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>