ArmVirtPkg: drop unused Pcds from ArmVirt.dsc.inc
    
    A block of settings has been copied around ARM platforms for years.
    These are consumed only by Ebl, and since none of the ArmVirtPkg
    platforms use that, drop them.
    
    Contributed-under: TianoCore Contribution Agreement 1.1
    Signed-off-by: Leif Lindholm <leif.lindholm@linaro.org>
    Reviewed-by: Laszlo Ersek <lersek@redhat.com>