[MLIR] Apply clang-tidy fixes for misc-use-internal-linkage in CudaRuntimeWrappers.cpp (NFC)

Author: joker-eph

mlir/lib/ExecutionEngine/CudaRuntimeWrappers.cpp

@@ -57,7 +57,7 @@
 thread_local static int32_t defaultDevice = 0;
 
 /// Helper method that checks environment value for debugging.
-bool isDebugEnabled() {
+static bool isDebugEnabled() {
   const char *kDebugEnvironmentVariable = "MLIR_CUDA_DEBUG";
   static bool isEnabled = getenv(kDebugEnvironmentVariable) != nullptr;
   return isEnabled;
@@ -71,7 +71,7 @@ bool isDebugEnabled() {
   } while (0)
 
 // Returns default CUdevice
-CUdevice getDefaultCuDevice() {
+static CUdevice getDefaultCuDevice() {
   CUdevice device;
   CUDA_REPORT_IF_ERROR(cuDeviceGet(&device, /*ordinal=*/defaultDevice));
   return device;