OvmfPkg/SmbiosPlatformDxe: create Xen-specific module INF file
    
    "OvmfPkg/SmbiosPlatformDxe" is structured somewhat differently from the
    drivers duplicated and trimmed thus far in this series. The final QEMU and
    Xen versions will share a relatively significant amount of code, therefore
    duplicating the whole driver is less useful, even temporarily. Instead,
    duplicate the INF file, in preparation for customizing the entry point
    function.
    
    Because ArmVirtXen doesn't actually include OvmfPkg/SmbiosPlatformDxe [*],
    there is only one platform that's supposed to consume the new driver:
    OvmfXen. Switch OvmfXen to the new driver at once.
    
    [*] See commit 164cf4038357 ("OvmfPkg: SmbiosPlatformDxe: restrict current
        Xen code to IA32/X64", 2015-07-26).
    
    This patch is best viewed with "git show --find-copies-harder".
    
    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>