OvmfPkg: Copy 8254TimerDxe driver from PcAtChipsetPkg

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=1496

This commit copies the exact 8254TimerDxe driver from PcAtChipsetPkg to
OvmfPkg.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Ray Ni <ray.ni@intel.com>
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

OvmfPkg/8254TimerDxe/TimerExtra.uni

@@ -0,0 +1,14 @@
+// /** @file
+// Timer Localized Strings and Content
+//
+// Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
+//
+// SPDX-License-Identifier: BSD-2-Clause-Patent
+//
+// **/
+
+#string STR_PROPERTIES_MODULE_NAME
+#language en-US
+"8254 Timer DXE Driver"
+
+