OvmfPkg: Replace GUEST_TYPE with CC_GUEST_TYPE

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3902

Replace GUEST_TYPE with CC_GUEST_TYPE which is defined in
MdePkg/Include/ConfidentialComputingGuestAttr.h.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Zhiguang Liu <zhiguang.liu@intel.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>

OvmfPkg/Include/WorkArea.h

@@ -10,14 +10,7 @@
 #ifndef __OVMF_WORK_AREA_H__
 #define __OVMF_WORK_AREA_H__
 
-//
-// Guest type for the work area
-//
-typedef enum {
-  GUEST_TYPE_NON_ENCRYPTED,
-  GUEST_TYPE_AMD_SEV,
-  GUEST_TYPE_INTEL_TDX,
-} GUEST_TYPE;
+#include <ConfidentialComputingGuestAttr.h>
 
 //
 // Confidential computing work area header definition. Any change