[Kernel] Reduce some Kinect/camera related log spam

Mainly in Forza Horizon 2

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

@@ -152,6 +152,12 @@ X_HRESULT XamApp::DispatchMessageSync(uint32_t message, uint32_t buffer_ptr,
              args->unk1.get(), args->unk2.get(), args->unk3.get());
       return X_E_SUCCESS;
     }
+    case 0x0002B004: {
+      // Probably related to 0x0002B003, maybe camera/Kinect related.
+      // Seen in Forza Horizon 2.
+      XELOGD("XamUnk2B004, unimplemented");
+      return X_E_SUCCESS;
+    }
   }
   XELOGE(
       "Unimplemented XAM message app={:08X}, msg={:08X}, arg1={:08X}, "

src/xenia/kernel/xam/xam_nui.cc

@@ -74,6 +74,14 @@ dword_result_t XamNuiGetDeviceStatus_entry(
 }
 DECLARE_XAM_EXPORT1(XamNuiGetDeviceStatus, kNone, kStub);
 
+dword_result_t XamXStudioRequest_entry(dword_t request_type,
+                                       lpdword_t result_ptr) {
+  // Return failure to indicate XStudio/dev features not available.
+  XELOGW("XamXStudioRequest called, returning X_E_FAIL");
+  return X_E_FAIL;
+}
+DECLARE_XAM_EXPORT1(XamXStudioRequest, kNone, kStub);
+
 dword_result_t XamUserNuiGetUserIndex_entry(unknown_t unk, lpdword_t index) {
   return X_E_NO_SUCH_USER;
 }

src/xenia/kernel/xboxkrnl/xboxkrnl_video.cc

@@ -522,6 +522,17 @@ void VdSwap_entry(
 DECLARE_XBOXKRNL_EXPORT3(VdSwap, kVideo, kImplemented, kHighFrequency,
                          kImportant);
 
+dword_result_t PsCamDeviceRequest_entry(dword_t request_type,
+                                        lpvoid_t param_ptr) {
+  // Quietly return X_E_FAIL to keep from log spamming due to
+  // lack of proper implemenation. There might be a way to signal
+  // to the game not to do this, maybe in XamXStudioRequest return
+  // value?
+  // Seen in Forza Horizon 2
+  return X_E_FAIL;
+}
+DECLARE_XBOXKRNL_EXPORT1(PsCamDeviceRequest, kVideo, kStub);
+
 void RegisterVideoExports(xe::cpu::ExportResolver* export_resolver,
                           KernelState* kernel_state) {
   auto memory = kernel_state->memory();