OvmfPkg/UefiCpuPkg: Add CcExit prefix to the APIs of CcExitLib

OvmfPkg/UefiCpuPkg: Add CcExit prefix to the APIs of CcExitLib

BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=4123

APIs which are defined in CcExitLib.h are added with the CcExit prefix.
This is to make the APIs' name more meaningful.

This change impacts OvmfPkg/UefiCpuPkg.

Cc: Eric Dong <eric.dong@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>