This fixes the compile errors in loadImageSSE2.cpp.

BUG=angle:773

This reverts commit a93192369eb448e932bcdd1e08ae791aacfbe0c4.

Change-Id: I31bc419cd3930ae129903b935f49a3c9b27fc887
Reviewed-on: https://chromium-review.googlesource.com/238448Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>