eDP driver has dependency on the reference clock input. Many of the eDP parameters are calculated/configured based on the reference clock input.. These parameters include receiver detect, output lane speed, clock oscillator parameters etc.. On EVM, the reference clock input/crystal/OSC0 is 19.2MHz. This is why released SDK uses 19.2MHz reference clock input for eDP also.
This FAQ explains what changes are required for the other reference clock in the eDP driver.