Fix sample module_api_global for hip-clang

module_api_global relies on a HCC only feature which allows host code
to write to device variables. This feature does not exist in CUDA
or hip-clang, which causes the sample not working in CUDA or hip-clang.

This patch fixes the sample by using standard features of CUDA and
hip-clang. The fixed sample works in HCC, CUDA and hip-clang.

samples/0_Intro/module_api_global/vcpy_kernel.cpp

@@ -25,8 +25,7 @@ THE SOFTWARE.
 #define ARRAY_SIZE (16)
 
 __device__ float myDeviceGlobal;
-extern float myDeviceGlobalArray[16];
-;
+__device__ float myDeviceGlobalArray[16];
 
 extern "C" __global__ void hello_world(const float* a, float* b) {
     int tx = hipThreadIdx_x;