araw: fix samples count on raw audio

(regression from 46f782a9)

modules/codec/araw.c

@@ -332,6 +332,7 @@ static block_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
     else
     {
         decoder_UpdateAudioFormat( p_dec );
+        p_block->i_nb_samples = samples;
         p_block->i_buffer = samples * (p_sys->framebits / 8);
     }