OvmfPkg/XenAcpiPlatformDxe: remove OVMF's built-in ACPI tables
    
    Xen is an advanced hypervisor; no Xen guest can function correctly without
    the hypervisor's dynamically provided ACPI tables. Remove the built-in
    (fallback) tables from XenAcpiPlatformDxe -- and the OvmfXen platform.
    
    Remove any dependencies from XenAcpiPlatformDxe that are no longer needed.
    
    Cc: Anthony Perard <anthony.perard@citrix.com>
    Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
    Cc: Jordan Justen <jordan.l.justen@intel.com>
    Cc: Julien Grall <julien@xen.org>
    Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
    Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2122
    Signed-off-by: Laszlo Ersek <lersek@redhat.com>
    Message-Id: <20210526201446.12554-17-lersek@redhat.com>
    Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
    Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>