drm/nouveau/TBDdevinit: don't fail when PMU/PRE_OS is missing from VBIOS

This Falcon application doesn't appear to be present on some newer
systems, so let's not fail init if we can't find it.

TBD: is there a way to determine whether it *should* be there?
Signed-off-by: NBen Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nvkm/subdev/devinit/gm200.c

@@ -158,7 +158,8 @@ gm200_devinit_post(struct nvkm_devinit *base, bool post)
 	}
 
 	/* load and execute some other ucode image (bios therm?) */
-	return pmu_load(init, 0x01, post, NULL, NULL);
+	pmu_load(init, 0x01, post, NULL, NULL);
+	return 0;
 }
 
 static const struct nvkm_devinit_func