drm/{i915,xe}: Run DRM default client setup

Rework fbdev probing to support fbdev_probe in struct drm_driver
and remove the old fb_probe callback. Provide an initializer macro
that sets the callback in struct drm_driver according to the kernel
configuration. Call drm_client_setup_with_color_mode() to run the
kernel's default client setup for DRM.

This commit also prepares support for the kernel's drm_log client
(or any future client) in i915. Using drm_log will also require vmap
support in GEM objects.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241212170913.185939-11-tzimmermann@suse.de


Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>