add Grandstream to credits too

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@34043 65c4cc65-6c06-0410-ace0-fbb531ad65f3

CREDITS

@@ -27,8 +27,11 @@ Wasim - Hangup detect
 * Thanks to QuickNet Technologies for their donation of an Internet
 PhoneJack and Linejack card to the project.  (http://www.quicknet.net)
 
-* Thanks to VoipSupply for their donation of Sipuras to the project for
-	t38 testing. (http://www.voipsupply.com)
+* Thanks to VoipSupply for their donation of Sipura ATAs to the project for
+T.38 testing. (http://www.voipsupply.com)
+
+* Thanks to Grandstream for their donation of ATAs to the project for
+T.38 testing. (http://www.grandstream.com)
 
 === MISCELLANEOUS PATCHES ===
 Jim Dixon - Zapata Telephony and app_rpt