drm/msm/dpu: Drop unnecessary NULL checks after container_of in dpu_encoder

The result of container_of() operations is never NULL unless the embedded
element is the first element of the structure. This is not the case here.
The NULL checks on the result of container_of() are therefore unnecessary
and misleading. Remove them.

This change was made automatically with the following Coccinelle script.

@@
type t;
identifier v;
statement s;
@@

<+...
(
  t v = container_of(...);
|
  v = container_of(...);
)
  ...
  when != v
- if (\( !v \| v == NULL \) ) s
...+>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210525112904.1747066-1-linux@roeck-us.netReviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
[DB: fixed patch subject]
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c

@@ -1429,11 +1429,6 @@ static void dpu_encoder_off_work(struct work_struct *work)
 	struct dpu_encoder_virt *dpu_enc = container_of(work,
 			struct dpu_encoder_virt, delayed_off_work.work);
 
-	if (!dpu_enc) {
-		DPU_ERROR("invalid dpu encoder\n");
-		return;
-	}
-
 	dpu_encoder_resource_control(&dpu_enc->base,
 						DPU_ENC_RC_EVENT_ENTER_IDLE);
 
@@ -1777,11 +1772,6 @@ static void dpu_encoder_vsync_event_work_handler(struct kthread_work *work)
 			struct dpu_encoder_virt, vsync_event_work);
 	ktime_t wakeup_time;
 
-	if (!dpu_enc) {
-		DPU_ERROR("invalid dpu encoder\n");
-		return;
-	}
-
 	if (dpu_encoder_vsync_time(&dpu_enc->base, &wakeup_time))
 		return;