Declare the PIX_FMT_GRAY8 pixel format as a paletted format. This is

consistent with the allocation currently done for PIX_FMT_GRAY8
pictures.

No significant slow-downs have been measured.

See the thread:
Subject: [FFmpeg-devel] [PATCH] Is gray8 a paletted format?
Date: Sun, 15 Nov 2009 23:36:03 +0100

Originally committed as revision 22191 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavutil/pixdesc.c

@@ -199,6 +199,7 @@ const AVPixFmtDescriptor av_pix_fmt_descriptors[PIX_FMT_NB] = {
         .comp = {
             {0,0,1,0,7},        /* Y */
         },
+        .flags = PIX_FMT_PAL,
     },
     [PIX_FMT_MONOWHITE] = {
         .name = "monow",