lavfi/yadif: fix shorthand/option mismatch

Fix trac ticket #2128.
Signed-off-by: Stefano Sabatini <stefasab@gmail.com>

libavfilter/vf_yadif.c

@@ -369,7 +369,7 @@ static int query_formats(AVFilterContext *ctx)
 static av_cold int init(AVFilterContext *ctx, const char *args)
 {
     YADIFContext *yadif = ctx->priv;
-    static const char *shorthand[] = { "mode", "parity", "enable", NULL };
+    static const char *shorthand[] = { "mode", "parity", "deint", NULL };
     int ret;
 
     yadif->csp = NULL;