indeo2: init_get_bits size in bits instead of bytes

(cherry picked from commit 68ca330cbd)

Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavcodec/indeo2.c

@@ -165,7 +165,7 @@ static int ir2_decode_frame(AVCodecContext *avctx,
 #endif
     start = 48; /* hardcoded for now */
 
-    init_get_bits(&s->gb, buf + start, buf_size - start);
+    init_get_bits(&s->gb, buf + start, (buf_size - start) * 8);
 
     if (s->decode_delta) { /* intraframe */
         ir2_decode_plane(s, avctx->width, avctx->height,