drm/i915/cdclk: Drop tgl/dg2 cdclk bump hacks

No one ever figured out why bumping the cdclk helped
with whatever issue we were having at the time.
Remove the hacks and start from scratch so that we
can actually see if any problems still remain.

Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240402155016.13733-4-ville.syrjala@linux.intel.com