Fix to Visual Studio build error.

signed/unsigned mismatch from commit: 918011.

Change-Id: I6b9bb3618f8e72ea4cc0e6ba8fb9b13676985ed0
diff --git a/vp8/encoder/onyx_if.c b/vp8/encoder/onyx_if.c
index e81c05e..298f50f 100644
--- a/vp8/encoder/onyx_if.c
+++ b/vp8/encoder/onyx_if.c
@@ -616,7 +616,7 @@
 
 #if CONFIG_TEMPORAL_DENOISING
         if (cpi->denoiser.aggressive_mode != 0 &&
-            Q < cpi->denoiser.denoise_pars.qp_thresh) {
+            Q < (int)cpi->denoiser.denoise_pars.qp_thresh) {
           // Under aggressive denoising mode, use segmentation to turn off loop
           // filter below some qp thresh. The loop filter is turned off for all
           // blocks that have been encoded as ZEROMV LAST x frames in a row,