access/alsa.c: Simplify demux loop.

(cherry picked from commit d3dd9028)

modules/access/alsa.c

@@ -360,16 +360,14 @@ static int Demux( demux_t *p_demux )
 
     do
     {
+        p_block = GrabAudio( p_demux );
         if( p_block )
         {
+            es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block->i_pts );
             es_out_Send( p_demux->out, p_sys->p_es, p_block );
             p_block = NULL;
         }
 
-        p_block = GrabAudio( p_demux );
-        if( p_block )
-            es_out_Control( p_demux->out, ES_OUT_SET_PCR, p_block->i_pts );
-
     } while( p_block && p_sys->i_next_demux_date > 0 &&
              p_block->i_pts < p_sys->i_next_demux_date );