Removes mismatching signs in signal_processing_unittests

Negative inputs was used in WebRtcSpl_NormU32() causing warnings.

BUG=3674
TESTED=locally and trybots
R=tina.legrand@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/17089004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@6870 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/common_audio/signal_processing/signal_processing_unittest.cc b/common_audio/signal_processing/signal_processing_unittest.cc
index 2e7d2d0..284fb83 100644
--- a/common_audio/signal_processing/signal_processing_unittest.cc
+++ b/common_audio/signal_processing/signal_processing_unittest.cc
@@ -136,11 +136,7 @@
     EXPECT_EQ(4, WebRtcSpl_NormW16(b32));
 
     EXPECT_EQ(0, WebRtcSpl_NormU32(0u));
-    // TODO(bjornv): figure out what the following line is trying to test and
-    // test that.
-    // EXPECT_EQ(0, WebRtcSpl_NormU32(-1u));
-    EXPECT_EQ(0,
-              WebRtcSpl_NormU32(static_cast<uint32_t>(WEBRTC_SPL_WORD32_MIN)));
+    EXPECT_EQ(0, WebRtcSpl_NormU32(0xffffffff));
     EXPECT_EQ(15, WebRtcSpl_NormU32(static_cast<uint32_t>(a32)));
 
     EXPECT_EQ(104, WebRtcSpl_AddSatW16(a16, b16));