FLACExtractor: copy protect mWriteBuffer

Bug: 30895578
Change-Id: I4cba36bbe3502678210e5925181683df9726b431

static void copyMultiCh24(short *dst, const int *const *src, unsigned nSamples, unsigned nChannels)
static void copyMultiCh24(short *dst, const int * src[FLACParser::kMaxChannels], unsigned nSamples, unsigned nChannels)
 {
     for (unsigned i = 0; i < nSamples; ++i) {
         for (unsigned c = 0; c < nChannels; ++c) {
 *dst++ = src[c][i] >> 8;
 }
 }
}

static void copyMultiCh24(short *dst, const int *const *src, unsigned nSamples, unsigned nChannels)
 {
     for (unsigned i = 0; i < nSamples; ++i) {
         for (unsigned c = 0; c < nChannels; ++c) {
 *dst++ = src[c][i] >> 8;
 }
 }
}
