drm/amd/display: fix gcc set but not used warning of variable 'link_b…

…andwidth_kbps'

apply_dsc_policy_for_stream() will only be used if
'CONFIG_DRM_AMD_DC_DCN' is enabled, thus the function can be
declared inside the ifdefine marco.

Fix gcc warning:
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:5577:11: warning:
 variable ‘link_bandwidth_kbps’ set but not used [-Wunused-but-set-variable]

Signed-off-by: Yu Kuai <yukuai3@huawei.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -5569,6 +5569,7 @@ static void update_dsc_caps(struct amdgpu_dm_connector *aconnector,
 	}
 }
 
+#if defined(CONFIG_DRM_AMD_DC_DCN)
 static void apply_dsc_policy_for_stream(struct amdgpu_dm_connector *aconnector,
 										struct dc_sink *sink, struct dc_stream_state *stream,
 										struct dsc_dec_dpcd_caps *dsc_caps)
@@ -5578,7 +5579,6 @@ static void apply_dsc_policy_for_stream(struct amdgpu_dm_connector *aconnector,
 
 	link_bandwidth_kbps = dc_link_bandwidth_kbps(aconnector->dc_link,
 							dc_link_get_link_cap(aconnector->dc_link));
-#if defined(CONFIG_DRM_AMD_DC_DCN)
 	/* Set DSC policy according to dsc_clock_en */
 	dc_dsc_policy_set_enable_dsc_when_not_needed(
 		aconnector->dsc_settings.dsc_force_enable == DSC_CLK_FORCE_ENABLE);