mgcp: We do not need to check for talloc_free

Simplify the code and remove null check for the two strings.
diff --git a/openbsc/src/libmgcp/mgcp_protocol.c b/openbsc/src/libmgcp/mgcp_protocol.c
index 54af15b..86f361c 100644
--- a/openbsc/src/libmgcp/mgcp_protocol.c
+++ b/openbsc/src/libmgcp/mgcp_protocol.c
@@ -996,15 +996,11 @@
 	endp->ci = CI_UNUSED;
 	endp->allocated = 0;
 
-	if (endp->callid) {
-		talloc_free(endp->callid);
-		endp->callid = NULL;
-	}
+	talloc_free(endp->callid);
+	endp->callid = NULL;
 
-	if (endp->local_options) {
-		talloc_free(endp->local_options);
-		endp->local_options = NULL;
-	}
+	talloc_free(endp->local_options);
+	endp->local_options = NULL;
 
 	mgcp_rtp_end_reset(&endp->bts_end);
 	mgcp_rtp_end_reset(&endp->net_end);