Disable FLAC__bitreader_read_rice_signed_block_asm_ia32_bswap.

Don't use the assembly function since it seems to be slower than
the current version of FLAC__bitreader_read_rice_signed_block.
Signed-off-by: Erik de Castro Lopo <erikd@mega-nerd.com>

src/libFLAC/stream_decoder.c

@@ -400,7 +400,7 @@ static FLAC__StreamDecoderInitStatus init_stream_internal_(
 #ifdef FLAC__CPU_IA32
 		FLAC__ASSERT(decoder->private_->cpuinfo.type == FLAC__CPUINFO_TYPE_IA32);
 #ifdef FLAC__HAS_NASM
-#if 1 /*@@@@@@ OPT: not clearly faster, needs more testing */
+#if 0 /*@@@@@@ OPT: seems to be slower than FLAC__bitreader_read_rice_signed_block */
 		if(decoder->private_->cpuinfo.data.ia32.bswap)
 			decoder->private_->local_bitreader_read_rice_signed_block = FLAC__bitreader_read_rice_signed_block_asm_ia32_bswap;
 #endif