fix compiling of chan_sip.c

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@128254 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -315,7 +315,7 @@ enum invitestates {
        \note Should be aligned to above table as index */
 static const struct invstate2stringtable {
 	const enum invitestates state;
-	const char const *desc;
+	const char *desc;
 } invitestate2string[] = {
 	{INV_NONE,              "None"  },
 	{INV_CALLING,           "Calling (Trying)"},