drm/i915: move property enums to intel_display_types.h

Move the property enums closer to home. Acually make the broadcast
macros an enum while at it.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/589d5449a504ec9742dc1fa8d4871d0d6d0cddca.1565085692.git.jani.nikula@intel.com