osmo_io: Clean up code

 - Remove osmo_io_init() from header, since it has no function definition
 - Add osmo_iofd_init() to header

Change-Id: I77f7ae2b211507f420d87c484ec75ee054fceb63
diff --git a/include/osmocom/core/osmo_io.h b/include/osmocom/core/osmo_io.h
index b780d9a..b3d248f 100644
--- a/include/osmocom/core/osmo_io.h
+++ b/include/osmocom/core/osmo_io.h
@@ -69,7 +69,7 @@
 	};
 };
 
-void osmo_io_init(void);
+void osmo_iofd_init(void);
 
 struct osmo_io_fd *osmo_iofd_setup(const void *ctx, int fd, const char *name,
 		  enum osmo_io_fd_mode mode, const struct osmo_io_ops *ioops, void *data);