non-const lvalue reference cannot bind to a temporary.

Change-Id: I561cc8cfcedace6aab949e6e496203f39af77e2e
Reviewed-on: https://swiftshader-review.googlesource.com/5594Reviewed-by: Nicolas Capens <capn@google.com>
Tested-by: Nicolas Capens <capn@google.com>