alsdec.c: Simplify error check before calling rice decoder.

Reviewed-by: Thilo Borgmann

libavcodec/alsdec.c

@@ -652,7 +652,7 @@ static int read_var_block_data(ALSDecContext *ctx, ALSBlockData *bd)
             s[k] = s[k - 1] + decode_rice(gb, 0);
     }
     for (k = 1; k < sub_blocks; k++)
-        if (s[k] < 0 || s[k] > 32) {
+        if (s[k] > 32) {
             av_log(avctx, AV_LOG_ERROR, "k invalid for rice code.\n");
             return -1;
         }