As a baby step towards making struct intel_display the main data
structure for display, add a backpointer to struct drm_device that can
be used instead of &i915->drm.
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/47dd7bc4aae3c10b18097824e37617c072c66c0b.1713358679.git.jani.nikula@intel.com