Change maximum number of sip clients supported to 10
This patch is a copy of https://dev.iopsys.eu/rdk-factory/provider/oem/askey/meta-rdk-askey/-/blob/devel/meta-rdk-iopsys/recipes-telephony/asterisk-chan-voicemngr/files/0001-Max_sip_clients.patch?ref_type=heads which is to be removed as we have rdk branch in asterisk-chan-voicemngr for RDK