drm/i915/dpll: Change param to intel_display in for_each_shared_dpll

drm/i915/dpll: Change param to intel_display in for_each_shared_dpll

Change the argument of for_each_shared_dpll to take intel_display which
helps move as an ongoing effort to get rid off the dependency on
drm_i915_private. Some opportunistic changes in intel_pch_refclk done
too.

--v2
-Prefer using &i915->display [Jani]

Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250212074542.3569452-3-suraj.kandpal@intel.com