OvmfPkg/ResetSystemLib: add driver for microvm

Uses the generic event device to reset and poweroff.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3599
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Jiewen Yao <Jiewen.yao@intel.com>

OvmfPkg/PlatformPei/Platform.c

@@ -161,6 +161,7 @@ MemMapInitialization (
   AddIoMemoryRangeHob (0x0A0000, BASE_1MB);
 
   if (mHostBridgeDevId == 0xffff /* microvm */) {
+    AddIoMemoryBaseSizeHob (MICROVM_GED_MMIO_BASE, SIZE_4KB);
     AddIoMemoryBaseSizeHob (0xFEC00000, SIZE_4KB); /* ioapic #1 */
     AddIoMemoryBaseSizeHob (0xFEC10000, SIZE_4KB); /* ioapic #2 */
     return;