drm/i915/display: convert params to struct intel_display

Going forward, struct intel_display shall replace struct
drm_i915_private as the main display device data pointer type. Convert
intel_display_params.[ch] and intel_display_debugfs_params.[ch] to
struct intel_display.

Some stragglers are left behind where needed.

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/3e5cc1744eaf4708b08303e3e7e194035d7941cc.1724342644.git.jani.nikula@intel.com


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