module_api sample: no longer need EXTERN_C workaround

Change-Id: Ida087d832df8e1f3620b38f920ec2853aad641c8


[ROCm/hip-tests commit: c63944fc08]

projects/hip-tests/samples/0_Intro/module_api/vcpy_kernel.cpp

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