Don't assume two input channels in uhjdecoder

utils/uhjdecoder.cpp

@@ -471,7 +471,7 @@ int main(int argc, char **argv)
             if(sgot < BufferLineSize)
             {
                 const sf_count_t remaining{std::min(BufferLineSize - sgot, LeadOut)};
-                std::fill_n(inmem.get() + sgot*2, remaining*2, 0.0f);
+                std::fill_n(inmem.get() + sgot*ininfo.channels, remaining*ininfo.channels, 0.0f);
                 sgot += remaining;
                 LeadOut -= remaining;
             }