firmware: more split out of firmware to sub packages
    
    The cirrus-audio/intel-audio/tiwilink/nxp sub packages are of
    exisiting firmware so we will pull them in on upgrade as
    default. The intel-vsc is for Camera ISPs and is new upstream
    so it's not installed by default yet.
    
    Signed-off-by: Peter Robinson <pbrobinson@gmail.com>