drm/msm/dpu: remove unused local variable 'cmd_enc'

Fixes the following W=1 kernel build warning:

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c: In function ‘dpu_encoder_phys_cmd_wait_for_commit_done’:
drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c:688:31: warning: variable ‘cmd_enc’ set but not used [-Wunused-but-set-variable]

Fixes: fe286893 ("drm/msm/dpu: Remove unused call in wait_for_commit_done")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20210407083334.2762-1-thunder.leizhen@huawei.comReviewed-by: Abhinav Kumar <abhinavk@codeaurora.org>
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_phys_cmd.c

@@ -678,10 +678,6 @@ static int dpu_encoder_phys_cmd_wait_for_tx_complete(
 static int dpu_encoder_phys_cmd_wait_for_commit_done(
 		struct dpu_encoder_phys *phys_enc)
 {
-	struct dpu_encoder_phys_cmd *cmd_enc;
-
-	cmd_enc = to_dpu_encoder_phys_cmd(phys_enc);
-
 	/* only required for master controller */
 	if (!dpu_encoder_phys_cmd_is_master(phys_enc))
 		return 0;