ACPI suspend: Fix CONFIG_ACPI_SLEEP dependence and some compilation warnings

Initially CONFIG_PM_SLEEP was defined as
CONFIG_SUSPEND || CONFIG_HIBERNATION and some ACPI code, most
importantly the code in drivers/acpi/main.c, was written with this
assumption.  Currently, however, CONFIG_PM_SLEEP is also set when
CONFIG_XEN_SAVE_RESTORE is set.

This causes some compilation warnings to appear in
drivers/acpi/main.c if both CONFIG_SUSPEND and CONFIG_HIBERNATION
are unset and CONFIG_PM_SLEEP is set (this was impossible before).
To fix this problem, redefine CONFIG_ACPI_SLEEP do depend directly
on CONFIG_SUSPEND || CONFIG_HIBERNATION, as originally intended, and
use it instead of CONFIG_PM_SLEEP in drivers/acpi/main.c, wherever
appropriate.

Additionally, move the acpi_target_sleep_state definition from under
the #ifdef to prevent compilation from failing in some cases.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/Kconfig

@@ -42,7 +42,7 @@ if ACPI
 
 config ACPI_SLEEP
 	bool
-	depends on PM_SLEEP
+	depends on SUSPEND || HIBERNATION
 	default y
 
 config ACPI_PROCFS

drivers/acpi/sleep/main.c

@@ -23,6 +23,7 @@
 #include "sleep.h"
 
 u8 sleep_states[ACPI_S_STATE_COUNT];
+static u32 acpi_target_sleep_state = ACPI_STATE_S0;
 
 static int acpi_sleep_prepare(u32 acpi_state)
 {
@@ -45,9 +46,7 @@ static int acpi_sleep_prepare(u32 acpi_state)
 	return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
-static u32 acpi_target_sleep_state = ACPI_STATE_S0;
-
+#ifdef CONFIG_ACPI_SLEEP
 /*
  * ACPI 1.0 wants us to execute _PTS before suspending devices, so we allow the
  * user to request that behavior by using the 'acpi_old_suspend_ordering'
@@ -132,7 +131,7 @@ static void acpi_pm_end(void)
 	 */
 	acpi_target_sleep_state = ACPI_STATE_S0;
 }
-#endif /* CONFIG_PM_SLEEP */
+#endif /* CONFIG_ACPI_SLEEP */
 
 #ifdef CONFIG_SUSPEND
 extern void do_suspend_lowlevel(void);