drm: adp: Add Apple Display Pipe driver

drm: adp: Add Apple Display Pipe driver

This display controller is present on M-series chips and is used
to drive the touchbar display.

Co-developed-by: Janne Grunau <j@jannau.net>
Signed-off-by: Janne Grunau <j@jannau.net>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Neal Gompa <neal@gompa.dev>
Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250224-adpdrm-v8-2-cccf96710f0f@gmail.com
Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>