Revert "spudec: set the subpicture original dimensions based on the SPU properties"

This reverts commit 9a0d9c98.

This only worked in menus because the size was not exactly as the source
and did not trigger the bug fixed by !6653.

modules/codec/spudec/parse.c

@@ -871,13 +871,6 @@ static int Render( decoder_t *p_dec, subpicture_t *p_spu,
     }
     vlc_spu_regions_push(&p_spu->regions, p_region);
 
-    if (p_spu->i_original_picture_width == 0 && p_spu->i_original_picture_height == 0)
-    {
-        assert(p_spu_properties->i_width != 0);
-        assert(p_spu_properties->i_height != 0);
-        p_spu->i_original_picture_width  = p_spu_properties->i_width;
-        p_spu->i_original_picture_height = p_spu_properties->i_height;
-    }
     p_region->b_absolute = true;
     p_region->i_x = p_spu_properties->i_x;
     p_region->i_y = p_spu_properties->i_y + p_spu_data->i_y_top_offset;