drm/amd/display: fix NULL dereference

The following patch will fix a minor issue where a debug message is
referencing an struct that has just being checked whether is null or
not. This has been noticed by using coccinelle, in the following output:

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c:540:25-29: ERROR: aconnector is NULL but dereferenced.

Fixes: 5d72e247 ("drm/amd/display: switch DC over to the new DRM logging macros")
Signed-off-by: José Pekkarinen <jose.pekkarinen@foxhound.fi>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -536,11 +536,8 @@ bool dm_helpers_dp_read_dpcd(
 
 	struct amdgpu_dm_connector *aconnector = link->priv;
 
-	if (!aconnector) {
-		drm_dbg_dp(aconnector->base.dev,
-			   "Failed to find connector for link!\n");
+	if (!aconnector)
 		return false;
-	}
 
 	return drm_dp_dpcd_read(&aconnector->dm_dp_aux.aux, address, data,
 				size) == size;