sgi encoder does not support pal8

Originally committed as revision 18791 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/sgienc.c

@@ -151,7 +151,7 @@ AVCodec sgi_encoder = {
     encode_init,
     encode_frame,
     NULL,
-    .pix_fmts= (enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGBA, PIX_FMT_PAL8, PIX_FMT_GRAY8, PIX_FMT_NONE},
+    .pix_fmts= (enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGBA, PIX_FMT_GRAY8, PIX_FMT_NONE},
     .long_name= NULL_IF_CONFIG_SMALL("SGI image"),
 };