DSPHLE: Remove unneeded calls to m_mail_handler.Clear()

It's cleared whenever the uCode changes, so there's no reason to clear it in a destructor or during initialization.

I've also renamed it to ClearPending.

Source/Core/Core/HW/DSPHLE/DSPHLE.cpp

@@ -67,7 +67,7 @@ void DSPHLE::SendMailToDSP(u32 mail)
 
 void DSPHLE::SetUCode(u32 crc)
 {
-  m_mail_handler.Clear();
+  m_mail_handler.ClearPending();
   m_ucode = UCodeFactory(crc, this, m_wii);
   m_ucode->Initialize();
 }
@@ -77,7 +77,7 @@ void DSPHLE::SetUCode(u32 crc)
 // Even callers are deleted.
 void DSPHLE::SwapUCode(u32 crc)
 {
-  m_mail_handler.Clear();
+  m_mail_handler.ClearPending();
 
   if (m_last_ucode && UCodeInterface::GetCRC(m_last_ucode.get()) == crc)
   {

Source/Core/Core/HW/DSPHLE/MailHandler.cpp

@@ -19,7 +19,6 @@ CMailHandler::CMailHandler()
 
 CMailHandler::~CMailHandler()
 {
-  Clear();
 }
 
 void CMailHandler::PushMail(u32 mail, bool interrupt, int cycles_into_future)
@@ -69,7 +68,7 @@ u16 CMailHandler::ReadDSPMailboxLow()
   return 0x00;
 }
 
-void CMailHandler::Clear()
+void CMailHandler::ClearPending()
 {
   while (!m_Mails.empty())
     m_Mails.pop();
@@ -84,7 +83,7 @@ void CMailHandler::Halt(bool _Halt)
 {
   if (_Halt)
   {
-    Clear();
+    ClearPending();
     PushMail(0x80544348);
   }
 }
@@ -93,7 +92,7 @@ void CMailHandler::DoState(PointerWrap& p)
 {
   if (p.IsReadMode())
   {
-    Clear();
+    ClearPending();
     int sz = 0;
     p.Do(sz);
     for (int i = 0; i < sz; i++)

Source/Core/Core/HW/DSPHLE/MailHandler.h

@@ -20,11 +20,15 @@ public:
 
   // TODO: figure out correct timing for interrupts rather than defaulting to "immediately."
   void PushMail(u32 mail, bool interrupt = false, int cycles_into_future = 0);
-  void Clear();
   void Halt(bool _Halt);
   void DoState(PointerWrap& p);
   bool HasPending() const;
 
+  // Clear any pending mail from the current uCode.  This is called by DSPHLE::SetUCode and
+  // DSPHLE::SwapUCode. Since pending mail is an abstraction for DSPHLE and not something that
+  // actually exists on real hardware, HLE implementations do not need to call this directly.
+  void ClearPending();
+
   u16 ReadDSPMailboxHigh();
   u16 ReadDSPMailboxLow();
 

Source/Core/Core/HW/DSPHLE/UCodes/AX.cpp

@@ -34,7 +34,6 @@ AXUCode::AXUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
 
 AXUCode::~AXUCode()
 {
-  m_mail_handler.Clear();
 }
 
 void AXUCode::Initialize()

Source/Core/Core/HW/DSPHLE/UCodes/CARD.cpp

@@ -18,7 +18,6 @@ CARDUCode::CARDUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
 
 CARDUCode::~CARDUCode()
 {
-  m_mail_handler.Clear();
 }
 
 void CARDUCode::Initialize()

Source/Core/Core/HW/DSPHLE/UCodes/GBA.cpp

@@ -75,7 +75,6 @@ GBAUCode::GBAUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
 
 GBAUCode::~GBAUCode()
 {
-  m_mail_handler.Clear();
 }
 
 void GBAUCode::Initialize()

Source/Core/Core/HW/DSPHLE/UCodes/ROM.cpp

@@ -34,7 +34,6 @@ ROMUCode::~ROMUCode()
 
 void ROMUCode::Initialize()
 {
-  m_mail_handler.Clear();
   m_mail_handler.PushMail(0x8071FEED);
 }
 

Source/Core/Core/HW/DSPHLE/UCodes/Zelda.cpp

@@ -130,7 +130,6 @@ ZeldaUCode::ZeldaUCode(DSPHLE* dsphle, u32 crc) : UCodeInterface(dsphle, crc)
 
 ZeldaUCode::~ZeldaUCode()
 {
-  m_mail_handler.Clear();
 }
 
 void ZeldaUCode::Initialize()