Typo fix and add missing CMake template

Signed-off-by: Peter Lemenkov <lemenkov@gmail.com>

apps/sbc/etc/symmetricrtp.sbcprofile.conf

@@ -17,5 +17,5 @@ rtprelay_force_symmetric_rtp=yes
 # use symmetric RTP indication from P-MsgFlags flag 2
 #rtprelay_msgflags_symmetric_rtp=yes
 
-#-# outbound interface to use:
-#-#outbound_interface=extern
+# outbound interface to use:
+#outbound_interface=extern

apps/sbc/etc/symmetricrtp.sbcprofile.conf.cmake

@@ -0,0 +1,21 @@
+# symmetricrtp SBC profile
+#
+# This implements a transparent B2BUA which relays RTP and forces
+# symmetric RTP on both sides - thus being able to bridge between
+# two NATed clients
+
+# RURI/From/To defaults: transparent
+#RURI=$r
+#From=$f
+#To=$t
+
+## RTP relay
+# enable RTP relaying (bridging):
+enable_rtprelay=yes
+# force symmetric RTP (start with passive mode):
+rtprelay_force_symmetric_rtp=yes
+# use symmetric RTP indication from P-MsgFlags flag 2
+#rtprelay_msgflags_symmetric_rtp=yes
+
+# outbound interface to use:
+#outbound_interface=extern