[mlir][tosa] Fix left shift that was implicitly converted to 64-bit

[rsuderman]

Summary

Missing long specifier so that a shift would occur in 64-bits rather
than implicitly in 32-bits.

mlir/lib/Dialect/Tosa/IR/TosaCanonicalizations.cpp

if (val.isExactlyValue(1.0))
       return lhs;
   }
 
   if (lhsAttr && lhsAttr.isSplat() && resultETy.isa<IntegerType>()) {
     auto val = lhsAttr.getSplatValue<APInt>();
     if (val.isZero())
       return lhsAttr;
     const int64_t shift = getShift();
-    const int64_t shifted = 1 << shift;
+    const int64_t shifted = 1L << shift;
     if (val.getSExtValue() == shifted)
       return rhs;
   }
 
   if (rhsAttr && rhsAttr.isSplat() && resultETy.isa<IntegerType>()) {
     auto val = rhsAttr.getSplatValue<APInt>();
+    const int64_t shift = getShift();
+    const int64_t shifted = 1L << shift;
     if (val.isZero())
       return rhsAttr;
-    if (val.getSExtValue() == (1 << getShift()))
+    if (val.getSExtValue() == shifted)
       return lhs;
   }
 
   return MulBinaryFolder(lhsAttr, rhsAttr, lhsTy, getShift());
 }
 
 OpFoldResult SubOp::fold(ArrayRef<Attribute> operands) {
   auto lhsTy = getInput1().getType().dyn_cast<RankedTensorType>();