combine several small .h in msc_common.h

For hysterical raisins, there are some header files that contain few
declarations, and where the name doesn't reflect the content. Combine them to
new msc_common.h:

- common.h
- common_cs.h
- osmo_msc.h

Change-Id: I9e3a587342f8d398fb27354a2f2475f8797cdb28
diff --git a/include/osmocom/msc/msc_common.h b/include/osmocom/msc/msc_common.h
new file mode 100644
index 0000000..ffe8902
--- /dev/null
+++ b/include/osmocom/msc/msc_common.h
@@ -0,0 +1,22 @@
+#pragma once
+
+struct msgb;
+struct gsm_network;
+struct vlr_subscr;
+
+#define MSC_HLR_REMOTE_IP_DEFAULT "127.0.0.1"
+#define MSC_HLR_REMOTE_PORT_DEFAULT OSMO_GSUP_PORT
+
+enum nsap_addr_enc {
+	NSAP_ADDR_ENC_X213,
+	NSAP_ADDR_ENC_V4RAW,
+};
+
+typedef int (*mncc_recv_cb_t)(struct gsm_network *, struct msgb *);
+
+struct gsm_network *gsm_network_init(void *ctx, mncc_recv_cb_t mncc_recv);
+
+int msc_vlr_alloc(struct gsm_network *net);
+int msc_vlr_start(struct gsm_network *net);
+
+void msc_stop_paging(struct vlr_subscr *vsub);