vty: move vty_out_rate_ctr_group prototype to osmocom/vty/misc.h

Before this patch, it was in osmocom/core/rate_ctr.h
diff --git a/include/osmocom/core/rate_ctr.h b/include/osmocom/core/rate_ctr.h
index dba573d..9efc23d 100644
--- a/include/osmocom/core/rate_ctr.h
+++ b/include/osmocom/core/rate_ctr.h
@@ -75,7 +75,4 @@
 /* Initialize the counter module */
 int rate_ctr_init(void *tall_ctx);
 
-struct vty;
-void vty_out_rate_ctr_group(struct vty *vty, const char *prefix,
-			    struct rate_ctr_group *ctrg);
 #endif /* RATE_CTR_H */
diff --git a/include/osmocom/vty/Makefile.am b/include/osmocom/vty/Makefile.am
index d2f0616..83d0010 100644
--- a/include/osmocom/vty/Makefile.am
+++ b/include/osmocom/vty/Makefile.am
@@ -1,4 +1,4 @@
 osmovty_HEADERS = buffer.h command.h vector.h vty.h \
-	telnet_interface.h logging.h
+	telnet_interface.h logging.h misc.h
 
 osmovtydir = $(includedir)/osmocom/vty
diff --git a/include/osmocom/vty/misc.h b/include/osmocom/vty/misc.h
new file mode 100644
index 0000000..707f82f
--- /dev/null
+++ b/include/osmocom/vty/misc.h
@@ -0,0 +1,10 @@
+#ifndef OSMO_VTY_MISC_H
+#define OSMO_VTY_MISC_H
+
+#include <osmocom/vty/vty.h>
+#include <osmocom/core/rate_ctr.h>
+
+void vty_out_rate_ctr_group(struct vty *vty, const char *prefix,
+                            struct rate_ctr_group *ctrg);
+
+#endif