Minor fix of SRL zMIPS instruction type

was accidentally `slr` which generated unparseable zMIPS code.

Author: bzp99

src/main/java/org/twc/zerojavacompiler/kanga2zmips/Kanga2zMIPS.java

@@ -381,7 +381,7 @@ public String visit(Operator n) throws Exception {
         String[] retValue = {
                 "slt", "sle", "seq", "sne",         // comparison
                 "add", "sub", "mult", "div", "mod", // arithmetic
-                "and", "or", "xor", "sll", "slr"    // bitwise
+                "and", "or", "xor", "sll", "srl"    // bitwise
         };
         return retValue[n.f0.which];
     }
@@ -481,4 +481,4 @@ public String visit(Label n) throws Exception {
         return n.f0.toString();
     }
 
-}
+}