drm/i915/display: convert intel_has_pending_fb_unpin() to struct intel_display

drm/i915/display: convert intel_has_pending_fb_unpin() to struct intel_display

Going forward, struct intel_display is the main display device data
pointer. The intel_display.[ch] files are too big to convert in one
go. Convert intel_has_pending_fb_unpin() to struct intel_display.

Reviewed-by: Nemesa Garg <nemesa.garg@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/d70ad8f9cbba5ee32d985b76047b56996ad4b31e.1741084010.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>