drm/amdgpu: fix kgd_hqd_load failing to update shadow_wptr

The return value from copy_form_user is 0 for the success case.
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Andres Rodriguez <andresx7@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gfx_v8.c

@@ -252,7 +252,7 @@ static int kgd_hqd_load(struct kgd_dev *kgd, void *mqd, uint32_t pipe_id,
 	m = get_mqd(mqd);
 
 	valid_wptr = copy_from_user(&shadow_wptr, wptr, sizeof(shadow_wptr));
-	if (valid_wptr > 0)
+	if (valid_wptr == 0)
 		m->cp_hqd_pq_wptr = shadow_wptr;
 
 	acquire_queue(kgd, pipe_id, queue_id);