[Kernel/IO] IoCompletion: Removed !wait_ticks check

- Marked IoCompletion as frequently used functions
- Added correct behaviour to wait_ticks 0

src/xenia/kernel/xiocompletion.cc

@@ -30,7 +30,7 @@ bool XIOCompletion::WaitForNotification(uint64_t wait_ticks,
                                         IONotification* notify) {
   auto ms = std::chrono::milliseconds(TimeoutTicksToMs(wait_ticks));
   auto res = threading::Wait(notification_semaphore_.get(), false, ms);
-  if (res == threading::WaitResult::kSuccess || !wait_ticks) {
+  if (res == threading::WaitResult::kSuccess) {
     std::unique_lock<std::mutex> lock(notification_lock_);
     assert_false(notifications_.empty());