drm/amdgpu/display: fix warning when compiling without debugfs

fixes unused variable warning.
Reported-by: Eric Biggers <ebiggers@kernel.org>
Acked-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -4723,10 +4723,10 @@ amdgpu_dm_connector_atomic_duplicate_state(struct drm_connector *connector)
 static int
 amdgpu_dm_connector_late_register(struct drm_connector *connector)
 {
+#if defined(CONFIG_DEBUG_FS)
 	struct amdgpu_dm_connector *amdgpu_dm_connector =
 		to_amdgpu_dm_connector(connector);
 
-#if defined(CONFIG_DEBUG_FS)
 	connector_debugfs_init(amdgpu_dm_connector);
 #endif