cpuidle: replace xen access to x86 pm_idle and default_idle

When a Xen Dom0 kernel boots on a hypervisor, it gets access
to the raw-hardware ACPI tables.  While it parses the idle tables
for the hypervisor's beneift, it uses HLT for its own idle.

Rather than have xen scribble on pm_idle and access default_idle,
have it simply disable_cpuidle() so acpi_idle will not load and
architecture default HLT will be used.

cc: xen-devel@lists.xensource.com
Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 36719ea..b89f67d 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -122,6 +122,7 @@
 };
 
 #ifdef CONFIG_CPU_IDLE
+extern void disable_cpuidle(void);
 
 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 struct cpuidle_driver *cpuidle_get_driver(void);
@@ -135,6 +136,7 @@
 extern void cpuidle_disable_device(struct cpuidle_device *dev);
 
 #else
+static inline void disable_cpuidle(void) { }
 
 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 {return -ENODEV; }