[Offload] Make CUDA Driver Version a string (llvm#146049)

AMD treats this value as a string, so for consistency require this in
NVIDIA as well. This shouldn't change the output of the
`llvm-offload-device-info` tool, but does fix an issue in liboffload
when it tries to query the version.

Author: RossBrunton

offload/plugins-nextgen/cuda/src/rtl.cpp

@@ -930,7 +930,9 @@ struct CUDADeviceTy : public GenericDeviceTy {
 
     CUresult Res = cuDriverGetVersion(&TmpInt);
     if (Res == CUDA_SUCCESS)
-      Info.add("CUDA Driver Version", TmpInt);
+      // For consistency with other drivers, store the version as a string
+      // rather than an integer
+      Info.add("CUDA Driver Version", std::to_string(TmpInt));
 
     Info.add("CUDA OpenMP Device Number", DeviceId);