Replace dead assertion

As delta_q_present_flag is set to 0 if segment_quantizer_active is 1,
previous assert was never evaluated.

Change-Id: Ia89fffc2f82595198acd2630d5d5d5ba22d43633

av1/decoder/decodeframe.c

@@ -4745,9 +4745,7 @@ static size_t read_uncompressed_header(AV1Decoder *pbi,
       xd->prev_qindex = cm->base_qindex;
       cm->delta_q_res = 1 << aom_rb_read_literal(rb, 2);
 #if CONFIG_EXT_DELTA_Q
-      if (segment_quantizer_active) {
-        assert(seg->abs_delta == SEGMENT_DELTADATA);
-      }
+      assert(!segment_quantizer_active);
       cm->delta_lf_present_flag = aom_rb_read_bit(rb);
       if (cm->delta_lf_present_flag) {
         xd->prev_delta_lf_from_base = 0;