[Libomptarget][NFC] Fix unhandled allocator enum value

Author: jhuber6

openmp/libomptarget/plugins-nextgen/common/src/PluginInterface.cpp

@@ -1398,6 +1398,7 @@ Expected<void *> GenericDeviceTy::dataAlloc(int64_t Size, void *HostPtr,
 
   switch (Kind) {
   case TARGET_ALLOC_DEFAULT:
+  case TARGET_ALLOC_DEVICE_NON_BLOCKING:
   case TARGET_ALLOC_DEVICE:
     if (MemoryManager) {
       Alloc = MemoryManager->allocate(Size, HostPtr);