drm/amd/pm: remove unused num_of_active_display variable

clang with W=1 reports
drivers/gpu/drm/amd/amdgpu/../pm/swsmu/amdgpu_smu.c:1700:6: error: variable
  'num_of_active_display' set but not used [-Werror,-Wunused-but-set-variable]
        int num_of_active_display = 0;
            ^
This variable is not used so remove it.

Fixes: 75145aab ("drm/amdgpu/swsmu: clean up a bunch of stale interfaces")
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/pm/swsmu/amdgpu_smu.c

@@ -1712,8 +1712,6 @@ static int smu_display_configuration_change(void *handle,
 					    const struct amd_pp_display_configuration *display_config)
 {
 	struct smu_context *smu = handle;
-	int index = 0;
-	int num_of_active_display = 0;
 
 	if (!smu->pm_enabled || !smu->adev->pm.dpm_enabled)
 		return -EOPNOTSUPP;
@@ -1724,11 +1722,6 @@ static int smu_display_configuration_change(void *handle,
 	smu_set_min_dcef_deep_sleep(smu,
 				    display_config->min_dcef_deep_sleep_set_clk / 100);
 
-	for (index = 0; index < display_config->num_path_including_non_display; index++) {
-		if (display_config->displays[index].controller_id != 0)
-			num_of_active_display++;
-	}
-
 	return 0;
 }