drm/amdgpu: remove set but not used variable 'dig_connector'

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

drivers/gpu/drm/amd/amdgpu/atombios_dp.c: In function
‘amdgpu_atombios_dp_get_panel_mode’:
drivers/gpu/drm/amd/amdgpu/atombios_dp.c:364:36: warning: variable
‘dig_connector’ set but not used [-Wunused-but-set-variable]

It is never used, so can be removed.

Fixes: d38ceaf9 ("drm/amdgpu: add core driver (v4)")
Signed-off-by: yu kuai <yukuai3@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/atombios_dp.c

@@ -361,7 +361,6 @@ int amdgpu_atombios_dp_get_panel_mode(struct drm_encoder *encoder,
 			       struct drm_connector *connector)
 {
 	struct amdgpu_connector *amdgpu_connector = to_amdgpu_connector(connector);
-	struct amdgpu_connector_atom_dig *dig_connector;
 	int panel_mode = DP_PANEL_MODE_EXTERNAL_DP_MODE;
 	u16 dp_bridge = amdgpu_connector_encoder_get_dp_bridge_encoder_id(connector);
 	u8 tmp;
@@ -369,8 +368,6 @@ int amdgpu_atombios_dp_get_panel_mode(struct drm_encoder *encoder,
 	if (!amdgpu_connector->con_priv)
 		return panel_mode;
 
-	dig_connector = amdgpu_connector->con_priv;
-
 	if (dp_bridge != ENCODER_OBJECT_ID_NONE) {
 		/* DP bridge chips */
 		if (drm_dp_dpcd_readb(&amdgpu_connector->ddc_bus->aux,