Fix a code-gen issue related to reinterpret_cast

This is actually pretty straight-forward, a single "&" appears to have
simply been dropped from the following commit:

commit a05bc928e0835b2022d87955226677e381ff9abc
Author: Andrew Waterman <waterman@eecs.berkeley.edu>
Date:   Sun May 25 21:46:26 2014 -0700

    Support sparse ROMs

    These are useful both for speeding up combinational logic in C++
    and for attaining better synthesis QoR.

in case anyone is interested, the following code triggers the error

import Chisel._;
object Torture {
  def main(args: Array[String]): Unit = {
    chiselMain(args, () => Module(new Torture()));
  }
}
class Torture extends Module {
  class IO extends Bundle {
    val in0 = Bits(INPUT, width=65);
    val in1 = Bits(INPUT, width=65);
    val out0 = Bits(OUTPUT, width=65);
  }
  val io = new IO();
  val io_in0 = Bits(width = 65);
  io_in0 := io.in0;
  val io_in1 = Bits(width = 65);
  io_in1 := io.in1;
  val Torture2 = Bits(width = 65);
  Torture2 := io_in0 / io_in1;
  io.out0 := Torture2;
}

I'm not sure that the emitted code is actually wrong, as I don't know
much about what's going on here.  In other words, it could be correct
in this sparse ROM case, I just don't know how to even generate one.
This passes through the rest of my torture tester tests, so hopefully
it's OK?