drm/i915/dpio: Remove pointless variables from vlv/chv DPLL code

Drop all the local variables for the DPLL dividers for vlv/chv
and just consult the state directly.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240422083457.23815-6-ville.syrjala@linux.intel.com


Reviewed-by: Jani Nikula <jani.nikula@intel.com>