Adjust event times after a PPC clock change

This likely doesn't change much, but it makes events trigger at the
correct time after a clock change.

Source/Core/Core/CoreTiming.cpp

@@ -364,6 +364,16 @@ void LogPendingEvents()
   }
 }
 
+// Should only be called from the CPU thread after the PPC clock has changed
+void AdjustEventQueueTimes(u32 new_ppc_clock, u32 old_ppc_clock)
+{
+  for (Event& ev : s_event_queue)
+  {
+    const s64 ticks = (ev.time - g_global_timer) * new_ppc_clock / old_ppc_clock;
+    ev.time = g_global_timer + ticks;
+  }
+}
+
 void Idle()
 {
   if (SConfig::GetInstance().bSyncGPUOnSkipIdleHack)

Source/Core/Core/CoreTiming.h

@@ -91,6 +91,8 @@ void LogPendingEvents();
 
 std::string GetScheduledEventsSummary();
 
+void AdjustEventQueueTimes(u32 new_ppc_clock, u32 old_ppc_clock);
+
 u32 GetFakeDecStartValue();
 void SetFakeDecStartValue(u32 val);
 u64 GetFakeDecStartTicks();

Source/Core/Core/HW/SystemTimers.cpp

@@ -228,10 +228,12 @@ void PreInit()
 
 void ChangePPCClock(Mode mode)
 {
+  const u32 previous_clock = s_cpu_core_clock;
   if (mode == Mode::Wii)
     s_cpu_core_clock = 729000000u;
   else
     s_cpu_core_clock = 486000000u;
+  CoreTiming::AdjustEventQueueTimes(s_cpu_core_clock, previous_clock);
 }
 
 void Init()