UefiPayloadPkg: Get and enter DxeCore for Universal Payload

From gUniversalPayloadExtraDataGuid Guid Hob, get the Dxe FV information,
and get the Dxe Core from the FV.
Also, make sure if there are muliple FV hob, the FV hob pointing to this FV
will be the first in the hob list.

Cc: Maurice Ma <maurice.ma@intel.com>
Cc: Guo Dong <guo.dong@intel.com>
Cc: Benjamin You <benjamin.you@intel.com>
Reviewed-by: Guo Dong <guo.dong@intel.com>
Signed-off-by: Zhiguang Liu <zhiguang.liu@intel.com>

UefiPayloadPkg/UefiPayloadEntry/X64/DxeLoadFunc.c

@@ -66,8 +66,8 @@ HandOffToDxeCore (
   //
   // Get the address and size of the GHCB pages
   //
-  GhcbBase = (VOID *) PcdGet64 (PcdGhcbBase);
-  GhcbSize = PcdGet64 (PcdGhcbSize);
+  GhcbBase = 0;
+  GhcbSize = 0;
 
   PageTables = 0;
   if (FeaturePcdGet (PcdDxeIplBuildPageTables)) {