When -EPROBE_DEFER is returned do not raise an error, but silently return
this error instead. Fixes error like this:
[drm:drm_bridge_attach] *ERROR* failed to attach bridge
/soc@0/bus@30800000/mipi-dsi@30a00000 to encoder None-34: -517
[drm:drm_bridge_attach] *ERROR* failed to attach bridge
/soc@0/bus@30800000/mipi-dsi@30a00000 to encoder None-34: -517