Fixing SPIR codegen for Intel CPU device

It might seem trivial, but this pull request (finally!) enables SPIR (via spir64 target) to run on the Intel CPU OpenCL device on Ubuntu. As of this pull request, all of the tests should pass using the "spir64" target.

If you want to try it out, you can get the Intel CPU OpenCL implementation from here: http://software.intel.com/en-us/vcsource/tools/opencl-sdk-xe