:art: Remove unused functions in mpool.c

diff --git a/util b/util
index f28a1fed2973e5bf1806961709e7ebab0275ae5f..206eb445d3293941a6cb795743170fc5ca323b95 160000 (submodule)
--- a/util
+++ b/util
@@ -1 +1 @@
-Subproject commit f28a1fed2973e5bf1806961709e7ebab0275ae5f
+Subproject commit 206eb445d3293941a6cb795743170fc5ca323b95