xen64: set up syscall and sysenter entrypoints for 64-bit

We set up entrypoints for syscall and sysenter.  sysenter is only used
for 32-bit compat processes, whereas syscall can be used in by both 32
and 64-bit processes.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/xen/smp.c

@@ -69,6 +69,7 @@ static __cpuinit void cpu_bringup_and_idle(void)
 	preempt_disable();
 
 	xen_enable_sysenter();
+	xen_enable_syscall();
 
 	cpu = smp_processor_id();
 	smp_store_cpu_info(cpu);