avcodec/videotoolbox: use early return in videotoolbox_default_free

Cosmetic change only.
Signed-off-by: Aman Gupta <aman@tmm1.net>

libavcodec/videotoolbox.c

@@ -849,8 +849,9 @@ static int videotoolbox_default_init(AVCodecContext *avctx)
 static void videotoolbox_default_free(AVCodecContext *avctx)
 {
     AVVideotoolboxContext *videotoolbox = videotoolbox_get_context(avctx);
+    if (!videotoolbox)
+        return;
 
-    if (videotoolbox) {
     if (videotoolbox->cm_fmt_desc)
         CFRelease(videotoolbox->cm_fmt_desc);
 
@@ -858,7 +859,6 @@ static void videotoolbox_default_free(AVCodecContext *avctx)
         VTDecompressionSessionInvalidate(videotoolbox->session);
         CFRelease(videotoolbox->session);
     }
-    }
 }
 
 static int videotoolbox_uninit(AVCodecContext *avctx)