the dp helper would try to enable the i2c channel for rockchip-edp

[Randy Li]

Hello,

   Recently, I want to use a eDP panel in my RK3288 platform, but I got 
the following message:

[    8.935918] i2c i2c-6: of_i2c: modalias failure on /dp at ff970000/ports
[    8.936018] rockchip-drm display-subsystem: bound ff970000.dp (ops 
rockchip_dp_component_ops [analogix_dp_rockchip])
It try to enable the eDP aux channel and add a new I2C controller, but 
it failed then the whole display subsystem is broken, the panel doesn't 
power on either.

   I hope somebody could figure out what is wrong with it.