FreeSWITCH-FS-6836

Merge pull request #867 in FS/freeswitch from ~JFIRLES/freeswitch:bugfix/FS-9216-add-ua-update-display to master

* commit 'b36cef731c14eb73730b9e86b5dd533c20180eb4':
  FS-9216: [mod_sofia] Add Cisco SPA30X and Grandstream GXP user agents to send UPDATE