Fix generate_func to pass-by-value
Fix generate_func to pass-by-value

Seems that generate_func lambda function is being passed into the kernel function by reference. The signature is wrong and this is out of the spec, so generate_func should be passed by value. This is CUDA compliant.
ROCmSoftwarePlatform/rocRAND,ROCmSoftwarePlatform/rocRAND,ROCmSoftwarePlatform/rocRAND,ROCmSoftwarePlatform/rocRAND