module_api: workaround to use vcpy_kernel.cpp for NV path

Change-Id: Ib4868bf02c64070e846c19427c39289609909466

samples/0_Intro/module_api/vcpy_kernel.cpp

@@ -1,6 +1,12 @@
 #include<hip_runtime.h>
 
-__global__ void hello_world(hipLaunchParm lp, float *a, float *b)
+#ifdef __HIP_PLATFORM_NVCC__
+#define EXTERN_C extern "C"
+#else
+#define EXTERN_C
+#endif
+
+EXTERN_C __global__ void hello_world(hipLaunchParm lp, float *a, float *b)
 {
     int tx = hipThreadIdx_x;
     b[tx] = a[tx];