OvmfPkg/PlatformInitLib: factor out PlatformCpuCountBugCheck()

Move the QEMU v2.7 reset bug check/workaround to a separate function, as
we'll need to detect further issues.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
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: Jordan Justen <jordan.l.justen@intel.com>
Cc: Michael Brown <mcb30@ipxe.org>
Cc: Min Xu <min.m.xu@intel.com>
Cc: Oliver Steffen <osteffen@redhat.com>
Cc: Sebastien Boeuf <sebastien.boeuf@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Bugzilla: https://bugzilla.tianocore.org/show_bug.cgi?id=4250


Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20230119110131.91923-2-lersek@redhat.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Hugely-appreciated-by: Michael Brown <mcb30@ipxe.org>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>