Reduce max lowres from 5 to 3 in sp5x decoder

lowres higher than 3 crashes ffmpeg/ffplay here
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/sp5xdec.c

@@ -107,7 +107,7 @@ AVCodec ff_sp5x_decoder = {
     sp5x_decode_frame,
     CODEC_CAP_DR1,
     NULL,
-    .max_lowres = 5,
+    .max_lowres = 3,
     .long_name = NULL_IF_CONFIG_SMALL("Sunplus JPEG (SP5X)"),
 };