drm/msm/dpu: Remove set but not used variables 'mode', 'dpu_kms', 'priv'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c: In function dpu_encoder_virt_disable:
drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c:1199:27: warning: variable mode set but not used [-Wunused-but-set-variable]
drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c: In function _dpu_encoder_init_debugfs:
drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c:1963:18: warning: variable dpu_kms set but not used [-Wunused-but-set-variable]
drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c: In function dpu_encoder_frame_done_timeout:
drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c:2183:26: warning: variable priv set but not used [-Wunused-but-set-variable]

They are not used since commit 25fdd593 ("drm/msm:
Add SDM845 DPU support")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Rob Clark <robdclark@chromium.org>

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

@@ -1174,7 +1174,6 @@ static void dpu_encoder_virt_disable(struct drm_encoder *drm_enc)
 	struct dpu_encoder_virt *dpu_enc = NULL;
 	struct msm_drm_private *priv;
 	struct dpu_kms *dpu_kms;
-	struct drm_display_mode *mode;
 	int i = 0;
 
 	if (!drm_enc) {
@@ -1191,8 +1190,6 @@ static void dpu_encoder_virt_disable(struct drm_encoder *drm_enc)
 	mutex_lock(&dpu_enc->enc_lock);
 	dpu_enc->enabled = false;
 
-	mode = &drm_enc->crtc->state->adjusted_mode;
-
 	priv = drm_enc->dev->dev_private;
 	dpu_kms = to_dpu_kms(priv->kms);