Updated libopencm3 to the most recent sha.

esden · esden · commit 4c5ff5616864 · 2021-06-19T00:59:47.000-07:00
diff --git a/libopencm3 b/libopencm3
@@ -1 +1 @@
-Subproject commit cb0661f81de5b1cae52ca99c7b5985b678176db7
+Subproject commit 3b89fc5999874c49f6f5be65bbd5e75f7d77469c
