Fix C4434 warning about 32-bit shift assigned to 64-bits

webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.cc

Index: webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.cc
diff --git a/webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.cc b/webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.cc
index 04d36545216879d464065a62d773f3abb8d74dbd..268b77b93b5e544014f4e8ebf5b6e703cfba4b1e 100644
--- a/webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.cc
+++ b/webrtc/modules/audio_processing/intelligibility/intelligibility_enhancer.cc
@@ -93,7 +93,7 @@ IntelligibilityEnhancer::IntelligibilityEnhancer(int sample_rate_hz,
             43.f));
   start_freq_ = std::max(static_cast<size_t>(1), erb_index * kErbResolution);
 
-  size_t window_size = static_cast<size_t>(1 << RealFourier::FftOrder(freqs_));
+  size_t window_size = static_cast<size_t>(1) << RealFourier::FftOrder(freqs_);
   std::vector<float> kbd_window(window_size);
   WindowGenerator::KaiserBesselDerived(kKbdAlpha, window_size,
                                        kbd_window.data());