lm32: update

diff --git a/verilog/lm32/submodule b/verilog/lm32/submodule
index 57d998d38fa1cd77c1c5eed72f079aaa2b0b0721..cf2281b28e42c99ea9ed17fb2195608df24c1f89 160000 (submodule)
--- a/verilog/lm32/submodule
+++ b/verilog/lm32/submodule
@@ -1 +1 @@
-Subproject commit 57d998d38fa1cd77c1c5eed72f079aaa2b0b0721
+Subproject commit cf2281b28e42c99ea9ed17fb2195608df24c1f89