swr: Fix swresample.c:293:5: warning: passing argument 2 of ‘fill_audiodata’ from incompatible pointer type

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libswresample/swresample.c

@@ -290,7 +290,7 @@ int swr_convert(struct SwrContext *s, uint8_t *out_arg[SWR_CH_MAX], int out_coun
         out_count = in_count;
     }
 
-    fill_audiodata(in ,  in_arg);
+    fill_audiodata(in ,  (void*)in_arg);
     fill_audiodata(out, out_arg);
 
     if(s->full_convert){