fix new issue for global variables

1. The w2ll will crash if compile the code like that:
```
int sre_random(void)
{
  long  rnd1;
  static long  tbl[64];
  int i;
  for (i = 0; i < 64; i++) {
        tbl[i] = rnd1;
        if (tbl[i] < 0)
                tbl[i] += 0;
  }
  return 0;
}
```

2. Error Log:
```
w2ll: /workspace/toolchain/llvm/llvm/lib/IR/Globals.cpp:472: void llvm::GlobalVariable::setInitializer(llvm::Constant*): Assertion `InitVal->getType() == getValueType() && "Initializer type must match GlobalVariable type"' failed. (xcalcc:571)
```

Signed-off-by: Zhijin Zeng <[email protected]>

osprey/ir_tools/whirl2llvm.cxx

@@ -4543,7 +4543,7 @@ void ST2llvm::operator() (UINT idx, ST *st) const {
       if (INITV_IDX val = ST_has_initv(st)) {
         gvar->setInitializer(whirl2llvm->INITV2llvm(Initv_Table[val], ST_type(st)));
       } else {
-        SetZeroInitializer(gvar, gvar->getType(), st);
+        SetZeroInitializer(gvar, gvar->getValueType(), st);
       }
 
       if (ST_is_const_var(st)) {