drm/i915: Relocate intel_crtc_update_active_timings()

Move intel_crtc_update_active_timings() into intel_vblank.c
where it more properly belongs.

Also do the s/dev_priv/i915/ modernization rename while at it.

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Mitul Golani <mitulkumar.ajitkumar.golani@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230310235828.17439-3-ville.syrjala@linux.intel.com