[PATCH] xen: fix building on ARM with CONFIG_HIBERNATE_CALLBACKS

[arnd@arndb.de (Arnd Bergmann)]

A recent bug fix for x86 broke Xen on ARM for the case that
CONFIG_HIBERNATE_CALLBACKS is enabled:

drivers/built-in.o: In function `do_suspend':
/git/arm-soc/drivers/xen/manage.c:134: undefined reference to `xen_arch_suspend'
drivers/built-in.o:(.debug_addr+0xc3f4): undefined reference to `xen_arch_suspend'

It is not clear to me what needs to be done here, but this
patch avoids the build error by adding a stub for the
missing function.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 2b953a5e99 ("xen: Suspend ticks on all CPUs during suspend")
---
Please review, and submit an alternate patch if this one turns
out to be incorrect.

diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index 0ce4f32017ea..034dc8acd47e 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -13,7 +13,13 @@ void xen_arch_post_suspend(int suspend_cancelled);
 
 void xen_timer_resume(void);
 void xen_arch_resume(void);
+#ifdef CONFIG_X86
 void xen_arch_suspend(void);
+#else
+static inline void xen_arch_suspend(void)
+{
+}
+#endif
 
 void xen_resume_notifier_register(struct notifier_block *nb);
 void xen_resume_notifier_unregister(struct notifier_block *nb);