lavfi/drawutils: Do not claim to support P016.

Fixes fate on big-endian.

libavfilter/drawutils.c

@@ -186,7 +186,7 @@ int ff_draw_init(FFDrawContext *draw, enum AVPixelFormat format, unsigned flags)
         return AVERROR(EINVAL);
     if (desc->flags & ~(AV_PIX_FMT_FLAG_PLANAR | AV_PIX_FMT_FLAG_RGB | AV_PIX_FMT_FLAG_PSEUDOPAL | AV_PIX_FMT_FLAG_ALPHA))
         return AVERROR(ENOSYS);
-    if (format == AV_PIX_FMT_P010LE || format == AV_PIX_FMT_P010BE)
+    if (format == AV_PIX_FMT_P010LE || format == AV_PIX_FMT_P010BE || format == AV_PIX_FMT_P016LE || format == AV_PIX_FMT_P016BE)
         return AVERROR(ENOSYS);
     for (i = 0; i < desc->nb_components; i++) {
         c = &desc->comp[i];

tests/ref/fate/filter-pixfmts-pad

@@ -22,7 +22,6 @@ gray16le            468bda6155bdc7a7a20c34d6e599fd16
 gray9le             f8f3dfe31ca5fcba828285bceefdab9a
 nv12                381574979cb04be10c9168540310afad
 nv21                0fdeb2cdd56cf5a7147dc273456fa217
-p016le              536a3b4c3b47d005f9ab033370cc1c3b
 rgb0                78d500c8361ab6423a4826a00268c908
 rgb24               17f9e2e0c609009acaf2175c42d4a2a5
 rgba                b157c90191463d34fb3ce77b36c96386