drm/i915/display: Use i915_gem_object_get_dma_address to get dma address

Works better for xe like that. obj is no longer const.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231204134946.16219-1-maarten.lankhorst@linux.intel.com


Reviewed-by: Jouni Högander <jouni.hogander@intel.com>