axmap: make axmap_first_free() static

Pulled from an earlier patch from Ming, that we no longer need.

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/lib/axmap.c b/lib/axmap.c
index 5b8cb30..68096d8 100644
--- a/lib/axmap.c
+++ b/lib/axmap.c
@@ -369,7 +369,7 @@
 	return (uint64_t) -1ULL;
 }
 
-uint64_t axmap_first_free(struct axmap *axmap)
+static uint64_t axmap_first_free(struct axmap *axmap)
 {
 	if (firstfree_valid(axmap))
 		return axmap->first_free;
diff --git a/lib/axmap.h b/lib/axmap.h
index edfeba8..3705a1d 100644
--- a/lib/axmap.h
+++ b/lib/axmap.h
@@ -11,7 +11,6 @@
 void axmap_set(struct axmap *axmap, uint64_t bit_nr);
 unsigned int axmap_set_nr(struct axmap *axmap, uint64_t bit_nr, unsigned int nr_bits);
 int axmap_isset(struct axmap *axmap, uint64_t bit_nr);
-uint64_t axmap_first_free(struct axmap *axmap);
 uint64_t axmap_next_free(struct axmap *axmap, uint64_t bit_nr);
 void axmap_reset(struct axmap *axmap);