OvmfPkg/CloudHv: Replace legacy 8254 PIT with local APIC timer

OvmfPkg/CloudHv: Replace legacy 8254 PIT with local APIC timer

Cloud Hypervisor doesn't emulate the legacy 8254 PIT, which is why
instead of relying on it as the timer UEFI services, rely on the
XenTimerDxe implementation. This is not Xen specific, as it simply uses
the local APIC timer triggering interrupts on the vector 32.

Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Jiewen Yao <Jiewen.yao@intel.com>
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>