Fix gpu_*register tests when memcpy_peer is explicitly disabled

tests/datawizard/gpu_ptr_register.c

@@ -80,7 +80,7 @@ check_result(unsigned *t, size_t size)
 }
 
 #ifdef STARPU_USE_CUDA
-#if CUDART_VERSION >= 4000
+#ifdef HAVE_CUDA_MEMCPY_PEER
 static int
 test_cuda(void)
 {
@@ -260,7 +260,7 @@ int main(int argc, char **argv)
 #endif
 
 #ifdef STARPU_USE_CUDA
-#if CUDART_VERSION >= 4000 /* We need thread-safety of CUDA */
+#ifdef HAVE_CUDA_MEMCPY_PEER
 	ret = test_cuda();
 	if (ret == 1)
 		goto fail;