[llvm] [Offload] Add olKernelMaxGroupSize (PR #142950)

[Joseph Huber via llvm-commits]

================
@@ -276,6 +276,9 @@ struct GenericKernelTy {
                            KernelLaunchParamsTy LaunchParams,
                            AsyncInfoWrapperTy &AsyncInfoWrapper) const = 0;
 
+  virtual Expected<size_t> maxGroupSize(GenericDeviceTy &GenericDevice,
----------------
jhuber6 wrote:

Don't think this need to be size_t, block sizes are coded as 64-bit values.

https://github.com/llvm/llvm-project/pull/142950