Split the thounsands autogenerated code out from ocl_stdlib header file.

Split the thounsands autogenerated code out from ocl_stdlib header file.

This patch split the three auto generated code segments from the
huge ocl_stdlib.h. And we rename ocl_stdlib.h to ocl_stdlib.tmpl.h.

The final ocl_stdlib.h will be generated at runtime. It will
insert the ocl_as.h/ocl_convert.h/ocl_vector (which is also
autogenerated at runtime) into ocl_stdlib.tmpl.h's proper positon.

After this patch, we will get a maintainable header file size.

Signed-off-by: Zhigang Gong <zhigang.gong@linux.intel.com>
Reviewed-by: He Junyan <junyan.he@inbox.com>
Reviewed-by: Simon Richter <Simon.Richter@hogyros.de>