drm/{i915, xe}/display: Move dsm registration under intel_driver

Move dsm register/unregister calls from the drivers to under
intel_display_driver register/unregister.

v2: Rebase only

Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250217200133.741758-1-rodrigo.vivi@intel.com


Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>