By changing the pixel clock and the length of the back porch, it is
possible to obtain a perfect 50 Hz refresh rate.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200408095830.8131-2-paul@crapouillou.netAcked-by: Sam Ravnborg <sam@ravnborg.org>