faad: Fix channel reordering loop.

(cherry picked from commit e6050c742c28f3ba714cbadda19e11dab1cdd625)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/codec/faad.c

@@ -437,7 +437,8 @@ static aout_buffer_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
 
         /* Convert frame.channel_position to our own channel values */
         p_dec->fmt_out.audio.i_physical_channels = 0;
-        for( i = 0; i < frame.channels; i++ )
+        const uint32_t nbChannels = frame.channels;
+        for( i = 0; i < nbChannels; i++ )
         {
             /* Find the channel code */
             for( j = 0; j < MAX_CHANNEL_POSITIONS; j++ )