Clear FF_INPUT_BUFFER_PADDING_SIZE bytes at the end of the temporary buffer...

Clear FF_INPUT_BUFFER_PADDING_SIZE bytes at the end of the temporary buffer used in motion pixels decoder.
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/motionpixels.c

@@ -253,6 +253,7 @@ static int mp_decode_frame(AVCodecContext *avctx,
     mp->dsp.bswap_buf((uint32_t *)mp->bswapbuf, (const uint32_t *)buf, buf_size / 4);
     if (buf_size & 3)
         memcpy(mp->bswapbuf + (buf_size & ~3), buf + (buf_size & ~3), buf_size & 3);
+    memset(mp->bswapbuf + buf_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
     init_get_bits(&gb, mp->bswapbuf, buf_size * 8);
 
     memset(mp->changes_map, 0, avctx->width * avctx->height);

tests/ref/fate/motionpixels

@@ -109,4 +109,4 @@
 0, 648003, 230400, 0xb343f372
 0, 654003, 230400, 0xf7f1e588
 0, 660003, 230400, 0x9682bdb2
-0, 666003, 230400, 0x538a3db8
+0, 666003, 230400, 0x16f9aad8