hle: Get rid of global access to g_reschedule

This shouldn't be directly exposed if there's already a partial API that operates on it.
We can just provide the rest of that API.

src/core/hle/kernel/thread.cpp

@@ -483,7 +483,8 @@ void Reschedule() {
 
     Thread* cur = GetCurrentThread();
     Thread* next = PopNextReadyThread();
-    HLE::g_reschedule = false;
+
+    HLE::DoneRescheduling();
 
     // Don't bother switching to the same thread
     if (next == cur)