Add support for eDP displays

On some eDP displays the AUX-bus does not work properly. For those displays the timings and all that stuff that is usualy read from the EDID is read from the device tree by the driver.

The SECO panel-driver has been imported from linux-seco-imx, timings have been made optional for eDP and delays have been added.

In the SECO version of the mediatek (e)DP driver EDID support can be disabled for those display to fall back to the timings provided by the driver.