drm/kmb: Work around for higher system clock

Use a different value for system clock offset in the
ppl/llp ratio calculations for clocks higher than 500 Mhz.

Fixes: 98521f4d ("drm/kmb: Mipi DSI part of the display driver")
Signed-off-by: Anitha Chrisanthus <anitha.chrisanthus@intel.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211013233632.471892-1-anitha.chrisanthus@intel.com


Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>