x86: xen: move cpu_up functions out of ifdef

Three newly introduced functions are not defined when CONFIG_XEN_PVHVM is
disabled, but are still being used:

arch/x86/xen/enlighten.c:141:12: warning: ‘xen_cpu_up_prepare’ used but never defined
arch/x86/xen/enlighten.c:142:12: warning: ‘xen_cpu_up_online’ used but never defined
arch/x86/xen/enlighten.c:143:12: warning: ‘xen_cpu_dead’ used but never defined

Fixes: 4d737042 ("xen/x86: Convert to hotplug state machine")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>

arch/x86/xen/enlighten.c

@@ -1838,6 +1838,7 @@ static void __init init_hvm_pv_info(void)
 
 	xen_domain_type = XEN_HVM_DOMAIN;
 }
+#endif
 
 static int xen_cpu_up_prepare(unsigned int cpu)
 {
@@ -1888,6 +1889,7 @@ static int xen_cpu_up_online(unsigned int cpu)
 	return 0;
 }
 
+#ifdef CONFIG_XEN_PVHVM
 #ifdef CONFIG_KEXEC_CORE
 static void xen_hvm_shutdown(void)
 {