gsm_trx_burst_if: allow to customize the bind address

Pleviously remote address for DATA interface was also used as the
bind address, what is definitely wrong. Let's change the API a bit
in order to allow one to specify a custom bind address.

Change-Id: I6e5f7b7119ac454217b8dd04f9ee0dd3b23972b6
diff --git a/lib/misc_utils/udp_socket.cc b/lib/misc_utils/udp_socket.cc
index 73393a0..c43f183 100644
--- a/lib/misc_utils/udp_socket.cc
+++ b/lib/misc_utils/udp_socket.cc
@@ -38,8 +38,9 @@
   namespace gsm {
 
     udp_socket::udp_socket(
-      const std::string &remote_addr,
+      const std::string &bind_addr,
       const std::string &src_port,
+      const std::string &remote_addr,
       const std::string &dst_port,
       size_t mtu)
     {
@@ -50,7 +51,7 @@
       udp::resolver resolver(d_io_service);
 
       udp::resolver::query rx_query(
-        udp::v4(), remote_addr, src_port,
+        udp::v4(), bind_addr, src_port,
         boost::asio::ip::resolver_query_base::passive);
       udp::resolver::query tx_query(
         udp::v4(), remote_addr, dst_port,