h264 Fix: "warning: assigning to 'uint8_t *' (aka 'unsigned char *') from 'const uint8_t *' (aka 'const unsigned char *') discards qualifiers"

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/h264.c

@@ -3791,7 +3791,7 @@ static int decode_nal_units(H264Context *h, const uint8_t *buf, int buf_size){
         int consumed;
         int dst_length;
         int bit_length;
-        uint8_t *ptr;
+        const uint8_t *ptr;
         int i, nalsize = 0;
         int err;