Bug in FD BWE memory updates at low bitrates

The FD BWE memory updates in the function wb_pre_proc_ivas_fx() are missing due to a bug in the following condition:

IF( ( NE_16( st_fx->extl, WB_BWE ) || ( EQ_16( st_fx->extl, WB_BWE ) && EQ_32( st_fx->total_brate, 0 ) ) ) && !ppp_mode )
{
    ....
}

The bug is that st_fx->total_brate is in reality never equal to 0. Comparing the BASOP code to FLP, the st->extl_brate should be used instead of it.