[Beignet] [PATCH] Add clGetKernelSubGroupInfoKHR to _cl_icd_dispatch table

[Rebecca N. Palmer]

> Now I see that the problem is the API cannot be used through ICD, but in OpenCL1.2 it is a vender extension.
Beignet may consider it a vendor extension, but ocl-icd doesn't: 
anything with a KHR or EXT name goes through the "check the dispatch 
table first" lookup process, whether or not it exists in the version of 
OpenCL the ICD says it supports.

> Should we use the ICD OpenCL2.0 API table of it?
If you mean my patch, yes.

> Or maybe we should not use clGetExtensionFunctionForPlatform or clGetExtensionFunction to get the API clGetKernelSubGroupInfoKHR?
The alternative of just calling clGetKernelSubGroupInfoKHR without such 
a lookup also goes through the address table when used via ICD, so it 
will have the same problem...plus the additional problem of being a 
compile-time error on older versions of ocl-icd that don't know about 
this function.  (If you want to see the code that does this, build 
ocl-icd then look in ocl_icd_loader_gen.c)

If you want the warning to go away, you'd need to update Beignet's 
headers to 2.0+ (we already do that in Debian (for different reasons), 
it doesn't change the 1.2 version Beignet reports via clGetDeviceInfo) 
*and* use a stricter check (OCL_ICD_IDENTIFIED_FUNCTIONS > 120), or 
suppress it via compiler option (though the latter might also suppress 
the warning if you accidentally put a function in the wrong slot - I 
haven't tried).