get rid of mgcp_internal.h

The file mgcp_internal.h still contains mostly definitions and types
that are relevant for mgcp_network.c and mgcp_protocol.c. Lets give
the network and protocol module its own header files, also move stuff
that does not relate to protocol and network to the appropiate places.

Change-Id: I837eaad771ed7252304db4a81c37953b70766fff
diff --git a/tests/mgcp/mgcp_test.c b/tests/mgcp/mgcp_test.c
index a050a0b..5ae321f 100644
--- a/tests/mgcp/mgcp_test.c
+++ b/tests/mgcp/mgcp_test.c
@@ -22,14 +22,14 @@
 #include <osmocom/mgcp/mgcp.h>
 #include <osmocom/mgcp/vty.h>
 #include <osmocom/mgcp/mgcp_common.h>
-#include <osmocom/mgcp/mgcp_internal.h>
+#include <osmocom/mgcp/mgcp_conn.h>
+#include <osmocom/mgcp/mgcp_protocol.h>
 #include <osmocom/mgcp/mgcp_stat.h>
 #include <osmocom/mgcp/mgcp_msg.h>
 #include <osmocom/mgcp/mgcp_endp.h>
 #include <osmocom/mgcp/mgcp_trunk.h>
 #include <osmocom/mgcp/mgcp_sdp.h>
 #include <osmocom/mgcp/mgcp_codec.h>
-#include <osmocom/mgcp/mgcp_internal.h>
 
 #include <osmocom/core/application.h>
 #include <osmocom/core/talloc.h>