avfilter/[vf_nnedi, vf_estdif]: check interlaced flag on correct frame

Fixes regression in vf_nnedi after
24dc6d386c and vf_estdif while at it.

Signed-off-by: Kacper Michajłow <kasper93@gmail.com>

libavfilter/vf_estdif.c

@@ -498,7 +498,7 @@ static int config_input(AVFilterLink *inlink)
         return 0;
     }
 
-    if ((s->deint && !in->interlaced_frame) || ctx->is_disabled) {
+    if ((s->deint && !s->prev->interlaced_frame) || ctx->is_disabled) {
         s->prev->pts *= 2;
         ret = ff_filter_frame(ctx->outputs[0], s->prev);
         s->prev = in;

libavfilter/vf_nnedi.c

@@ -694,7 +694,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
         return 0;
     }
 
-    if ((s->deint && !in->interlaced_frame) || ctx->is_disabled) {
+    if ((s->deint && !s->prev->interlaced_frame) || ctx->is_disabled) {
         s->prev->pts *= 2;
         ret = ff_filter_frame(ctx->outputs[0], s->prev);
         s->prev = in;