arch-x86: Add Python 3 workarounds for long

Python 3 doesn't have a separate long type. Make long an alias for int
where needed to maintain compatibility.

This is aligning with https://gem5-review.googlesource.com/c/15988

Change-Id: I20e52d7f796d143534fa7dabeb6ff0ae8b62fd2b
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/26257
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

src/arch/x86/isa/microops/limmop.isa

@@ -101,6 +101,10 @@ def template MicroLimmOpConstructor {{
 }};
 
 let {{
+    import six
+    if six.PY3:
+        long = int
+
     class LimmOp(X86Microop):
         def __init__(self, dest, imm, dataSize="env.dataSize"):
             self.className = "Limm"