Check for minimal int size

Signed-off-by: Rafal Kapuscik <rkapuscik@antmicro.com>

systemverilog-plugin/UhdmAst.cc

diff --git a/systemverilog-plugin/UhdmAst.cc b/systemverilog-plugin/UhdmAst.cc
index a94767a..f461e17 100644
--- a/systemverilog-plugin/UhdmAst.cc
+++ b/systemverilog-plugin/UhdmAst.cc
@@ -1114,7 +1114,8 @@
             // yosys is assuming that int/uint is 32 bit, so we are setting here correct size
             // NOTE: it *shouldn't* break on explicite 64 bit const values, as they *should* be handled
             // above by vpi*StrVal
-            if (size == 64) {
+            // FIXME: Minimal int size should be resolved in UHDM, here we make sure it is at least 32
+            if (size == 64 || size < 32) {
                 size = 32;
                 is_signed = true;
             }