[mlir] Fix missing null termination in cuLinkAddData argument.

mlir/tools/mlir-cuda-runner/mlir-cuda-runner.cpp

RETURN_ON_CUDA_ERROR(cuLinkCreate(2,              /* number of jit options */
                                     jitOptions,     /* jit options */
                                     jitOptionsVals, /* jit option values */
                                     &linkState),
                        "cuLinkCreate");
 
   RETURN_ON_CUDA_ERROR(
       cuLinkAddData(linkState, CUjitInputType::CU_JIT_INPUT_PTX,
                     const_cast<void *>(static_cast<const void *>(ptx.c_str())),
-                    ptx.length(), name.data(), /* kernel name */
-                    0,                         /* number of jit options */
-                    nullptr,                   /* jit options */
-                    nullptr                    /* jit option values */
+                    ptx.length(), name.str().data(), /* kernel name */
+                    0,                               /* number of jit options */
+                    nullptr,                         /* jit options */
+                    nullptr                          /* jit option values */
                     ),
       "cuLinkAddData");
 
   void *cubinData;
   size_t cubinSize;
   RETURN_ON_CUDA_ERROR(cuLinkComplete(linkState, &cubinData, &cubinSize),
                        "cuLinkComplete");