drbd: silence -Wmissing-prototypes warnings

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

lib/lru_cache.c

diff --git a/lib/lru_cache.c b/lib/lru_cache.c
index 4a83ecd..6111cd1 100644
--- a/lib/lru_cache.c
+++ b/lib/lru_cache.c
@@ -169,7 +169,7 @@
 	return NULL;
 }
 
-void lc_free_by_index(struct lru_cache *lc, unsigned i)
+static void lc_free_by_index(struct lru_cache *lc, unsigned i)
 {
 	void *p = lc->lc_element[i];
 	WARN_ON(!p);