drm/nouveau/fifo/ga102: initialise chid on return from channel creation

Turns out caller isn't zero-initialised after-all.

Fixes: 49b2dfc0 ("drm/nouveau/ga102-: support ttm buffer moves via copy engine")
Reported-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Karol Herbst <kherbst@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210921090735.247236-1-skeggsb@gmail.comSigned-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

drivers/gpu/drm/nouveau/nvkm/engine/fifo/ga102.c

@@ -179,6 +179,9 @@ ga102_chan_new(struct nvkm_device *device,
 		return -ENODEV;
 
 	chan->ctrl.chan = nvkm_rd32(device, chan->ctrl.runl + 0x004) & 0xfffffff0;
+
+	args->chid = 0;
+	args->inst = 0;
 	args->token = nvkm_rd32(device, chan->ctrl.runl + 0x008) & 0xffff0000;
 
 	ret = nvkm_memory_new(device, NVKM_MEM_TARGET_INST, 0x1000, 0x1000, true, &chan->mthd);