power: move z_pm_save_idle_exit prototype to power.h

Maintain power prototypes in power.h instead of kernel and arch headers.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>
diff --git a/arch/arm/core/aarch32/irq_manage.c b/arch/arm/core/aarch32/irq_manage.c
index 4b688fe..1576c07 100644
--- a/arch/arm/core/aarch32/irq_manage.c
+++ b/arch/arm/core/aarch32/irq_manage.c
@@ -27,6 +27,7 @@
 #include <sw_isr_table.h>
 #include <irq.h>
 #include <tracing/tracing.h>
+#include <power/power.h>
 
 extern void z_arm_reserved(void);
 
diff --git a/arch/posix/core/swap.c b/arch/posix/core/swap.c
index 824b63f..5877e2e 100644
--- a/arch/posix/core/swap.c
+++ b/arch/posix/core/swap.c
@@ -18,6 +18,7 @@
 #include "posix_core.h"
 #include "irq.h"
 #include "kswap.h"
+#include <power/power.h>
 
 int arch_swap(unsigned int key)
 {
diff --git a/include/arch/x86/ia32/arch.h b/include/arch/x86/ia32/arch.h
index 7dcc9b4..a643fe9 100644
--- a/include/arch/x86/ia32/arch.h
+++ b/include/arch/x86/ia32/arch.h
@@ -28,6 +28,7 @@
 
 #include <arch/common/addr_types.h>
 #include <arch/x86/ia32/segmentation.h>
+#include <power/power.h>
 
 #endif /* _ASMLANGUAGE */
 
@@ -234,12 +235,6 @@
 }
 
 #ifdef CONFIG_PM
-/*
- * FIXME: z_pm_save_idle_exit is defined in kernel.h, which cannot be
- *	  included here due to circular dependency
- */
-extern void z_pm_save_idle_exit(int32_t ticks);
-
 static inline void arch_irq_direct_pm(void)
 {
 	if (_kernel.idle) {
diff --git a/include/kernel.h b/include/kernel.h
index 8a3de24..378f1d8 100644
--- a/include/kernel.h
+++ b/include/kernel.h
@@ -4939,8 +4939,6 @@
 /**
  * @internal
  */
-extern void z_pm_save_idle_exit(int32_t ticks);
-
 #ifdef ARCH_EXCEPT
 /* This architecture has direct support for triggering a CPU exception */
 #define z_except_reason(reason)	ARCH_EXCEPT(reason)
diff --git a/include/power/power.h b/include/power/power.h
index b09b435..56baafe 100644
--- a/include/power/power.h
+++ b/include/power/power.h
@@ -318,6 +318,8 @@
  * @}
  */
 
+
+void z_pm_save_idle_exit(int32_t ticks);
 #endif /* CONFIG_PM */
 
 #ifdef __cplusplus