platform: Add weak symbol for cdc clock

CRs-Fixed: 501718
Change-Id: I534d2a4498594a2c812dccb4aa815d78cfc1f5aa
diff --git a/platform/init.c b/platform/init.c
index a809501..5001373 100644
--- a/platform/init.c
+++ b/platform/init.c
@@ -101,3 +101,7 @@
 {
 	return 0;
 }
+
+__WEAK void clock_config_cdc(uint8_t slot)
+{
+}