drm/panel-simple: Fix dotclock for Logic PD Type 28

drm/panel-simple: Fix dotclock for Logic PD Type 28

The currently listed dotclock disagrees with the currently
listed vrefresh rate. Change the dotclock to match the vrefresh.

Someone tell me which (if either) of the dotclock or vreresh is
correct?

Cc: Adam Ford <aford173@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200302203452.17977-22-ville.syrjala@linux.intel.com
Reviewed-by: Adam Ford <aford173@gmail.com>