bcache: Delete fuzz tester

This code has rotted and it hasn't been used in ages anyways.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 04636a7..e0cca36 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -135,7 +135,7 @@
 	return crc ^ 0xffffffffffffffffULL;
 }
 
-void bch_btree_node_read_done(struct btree *b)
+static void bch_btree_node_read_done(struct btree *b)
 {
 	const char *err = "bad btree header";
 	struct bset *i = b->sets[0].data;
@@ -1834,7 +1834,7 @@
 	return true;
 }
 
-bool bch_btree_insert_keys(struct btree *b, struct btree_op *op)
+static bool bch_btree_insert_keys(struct btree *b, struct btree_op *op)
 {
 	bool ret = false;
 	struct bkey *k;