Documentation: bindings: add dt documentation for rk3399 dmc

This patch adds the documentation for rockchip rk3399 dmc driver.

Signed-off-by: Lin Huang <hl@rock-chips.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
1 file changed