MdePkg/Tdx.h: Add TDVMCALL_STATUS_RETRY

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4572

TDVMCALL_STATUS_RETRY is defined in GHCI spec section 2.4.1.

Reference:
[GHCI]: TDX Guest-Host-Communication Interface v1.0
https://cdrdv2.intel.com/v1/dl/getContent/726790

Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Min Xu <min.m.xu@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Michael Roth <michael.roth@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Signed-off-by: Ceping Sun <cepingx.sun@intel.com>

MdePkg/Include/IndustryStandard/Tdx.h

@@ -103,6 +103,8 @@
 #define TDVMCALL_REPORT_FATAL_ERR    0x10003
 #define TDVMCALL_SETUP_EVENT_NOTIFY  0x10004
 
+#define TDVMCALL_STATUS_RETRY  0x1
+
 #pragma pack(1)
 typedef struct {
   UINT64    Data[6];