Improve usb timing accuracy

rpcs3/Emu/Cell/lv2/sys_usbd.cpp

@@ -636,6 +636,8 @@ void usb_handler_thread::operator()()
 		// Process asynchronous requests that are pending
 		libusb_handle_events_timeout_completed(ctx, &lusb_tv, nullptr);
 
+		u64 delay = 1'000;
+
 		// Process fake transfers
 		if (!fake_transfers.empty())
 		{
@@ -650,6 +652,13 @@ void usb_handler_thread::operator()()
 
 				if (transfer->expected_time > timestamp)
 				{
+					const u64 diff_time = transfer->expected_time - timestamp;
+
+					if (diff_time < delay)
+					{
+						delay = diff_time;
+					}
+
 					++it;
 					continue;
 				}
@@ -668,7 +677,7 @@ void usb_handler_thread::operator()()
 		if (handled_devices.empty())
 			thread_ctrl::wait_for(500'000);
 		else
-			thread_ctrl::wait_for(1'000);
+			thread_ctrl::wait_for(delay);
 	}
 }