include: remove internal definition that are now in libosmocore

Still in one separate patch for libosmocore, but they may become
part of mainline soon.
diff --git a/include/osmocom/abis/signal.h b/include/osmocom/abis/signal.h
new file mode 100644
index 0000000..cf5ad55
--- /dev/null
+++ b/include/osmocom/abis/signal.h
@@ -0,0 +1,17 @@
+#ifndef _OSMO_ABIS_SIGNAL_H_
+#define _OSMO_ABIS_SIGNAL_H_
+
+#include <osmocom/core/signal.h>
+
+/* signal subsystems. */
+enum {
+	SS_GLOBAL		= OSMO_SIGNAL_SS_ABIS_RESERVED,
+	SS_INPUT,
+};
+
+/* signal types. */
+enum {
+	S_GLOBAL_SHUTDOWN	= OSMO_SIGNAL_T_ABIS_RESERVED,
+};
+
+#endif