VP8LInitBitReader: remove dead store

`br->val` was initialized to 0 followed later by `value` without being
read in between.

Change-Id: Ifdd06becb5a0de0ffb2641102c73985b077ed778

src/utils/bit_reader_utils.c

@@ -141,7 +141,6 @@ void VP8LInitBitReader(VP8LBitReader* const br,
 
   br->buf = start;
   br->len = length;
-  br->val = 0;
   br->bit_pos = 0;
   br->eos = 0;