[XAM] Remove XMP polling throttle sleeps

Fixes audio in Tekken Tag 2 and Def Jam Icon. Improves framerates in
Radiant Silvergun and Split/Second.

src/xenia/kernel/xam/apps/xmp_app.cc

@@ -8,7 +8,6 @@
  */
 
 #include "xenia/kernel/xam/apps/xmp_app.h"
-#include "xenia/kernel/xthread.h"
 
 #include "xenia/base/logging.h"
 #include "xenia/emulator.h"
@@ -24,12 +23,6 @@ namespace apps {
 XmpApp::XmpApp(KernelState* kernel_state) : App(kernel_state, 0xFA) {}
 
 X_HRESULT XmpApp::XMPGetStatus(uint32_t state_ptr) {
-  if (!XThread::GetCurrentThread()->main_thread()) {
-    // Some stupid games will hammer this on a thread - induce a delay
-    // here to keep from starving real threads.
-    xe::threading::Sleep(std::chrono::milliseconds(1));
-  }
-
   if (!state_ptr) {
     return X_E_INVALIDARG;
   }
@@ -423,11 +416,6 @@ X_HRESULT XmpApp::DispatchMessageSync(uint32_t message, uint32_t buffer_ptr,
 
       *playback_controller_locked = !media_player->IsTitleInPlaybackControl();
 
-      if (!XThread::GetCurrentThread()->main_thread()) {
-        // Atrain spawns a thread 82437FD0 to call this in a tight loop forever.
-        xe::threading::Sleep(std::chrono::milliseconds(10));
-      }
-
       // Assert if game is not in control of playback.
       assert_true(media_player->GetPlaybackController() ==
                   apu::PlaybackController::Game);