Cosmetics: Replace -1 with PIX_FMT_NONE.

libavcodec/j2kdec.c

@@ -1078,5 +1078,5 @@ AVCodec ff_jpeg2000_decoder = {
     .capabilities = CODEC_CAP_EXPERIMENTAL,
     .long_name = NULL_IF_CONFIG_SMALL("JPEG 2000"),
     .pix_fmts =
-        (enum PixelFormat[]) {PIX_FMT_GRAY8, PIX_FMT_RGB24, -1}
+        (enum PixelFormat[]) {PIX_FMT_GRAY8, PIX_FMT_RGB24, PIX_FMT_NONE}
 };

libavcodec/mjpegenc.c

@@ -490,6 +490,6 @@ AVCodec ff_amv_encoder = {
     .init           = MPV_encode_init,
     .encode         = amv_encode_picture,
     .close          = MPV_encode_end,
-    .pix_fmts= (enum PixelFormat[]){PIX_FMT_YUVJ420P, PIX_FMT_YUVJ422P, -1},
+    .pix_fmts= (enum PixelFormat[]){PIX_FMT_YUVJ420P, PIX_FMT_YUVJ422P, PIX_FMT_NONE},
     .long_name      = NULL_IF_CONFIG_SMALL("AMV Video"),
 };