platedetector: Add missing m library linking
platedetector: Add missing m library linking

Change-Id: I573155fc45cad214784da2a2d570acbe691c13b2

TribeMedia/kms-core,ESTOS/kms-core,Kurento/kms-core,KurentoLegacy/gst-kurento-plugins,KurentoLegacy/gst-kurento-plugins,TribeMedia/kms-core,ESTOS/kms-core,Kurento/kms-core,KurentoLegacy/gst-kurento-plugins,shelsonjava/kms-core,shelsonjava/kms-core,shelsonjava/kms-core,KurentoLegacy/gst-kurento-plugins,ESTOS/kms-core,TribeMedia/kms-core,shelsonjava/kms-core,Kurento/kms-core,ESTOS/kms-core,Kurento/kms-core,TribeMedia/kms-core