修复编译警告

webrtc/RtpExt.cpp

@@ -189,7 +189,7 @@ map<uint8_t/*id*/, RtpExt/*data*/> RtpExt::getExtValue(const RtpHeader *header)
         appendExt<RtpExtOneByte>(ret, ptr, end);
         return ret;
     }
-    if (reserved & 0xFFF0 == kTwoByteHeader) {
+    if ((reserved & 0xFFF0) == kTwoByteHeader) {
         appendExt<RtpExtTwoByte>(ret, ptr, end);
         return ret;
     }