Ported from nouveau.

v2: re-enable runtime autosuspend in the error case
Acked-by: NEdward O'Callaghan <funfunctor@folklore1984.net>
Reviewed-by: NMichel Dänzer <michel.daenzer@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>