plugins: add MM_PLUGIN_REQUIRED_QCDM to plugins requiring QCDM

The new QCDM port probing and grabbing mechanism implements a new
property for detecting the plugins which require the QCDM port to
be probed and grabbed.

Add the property to the affected plugins.

plugins/via/mm-plugin-via.c

@@ -66,6 +66,7 @@ mm_plugin_create (void)
                       MM_PLUGIN_ALLOWED_SUBSYSTEMS,      subsystems,
                       MM_PLUGIN_ALLOWED_PRODUCT_STRINGS, product_strings,
                       MM_PLUGIN_ALLOWED_AT,              TRUE,
+                      MM_PLUGIN_REQUIRED_QCDM,           TRUE,
                       NULL));
 }