ACPI / PM: Allow device power states to be used for CONFIG_PM unset

Currently, drivers/acpi/device_pm.c depends on CONFIG_PM and all of
the functions defined in there are replaced with static inline stubs
if that option is unset.  However, CONFIG_PM means, roughly, "runtime
PM or suspend/hibernation support" and some of those functions are
useful regardless of that.  For example, they are used by the ACPI
fan driver for controlling fans and acpi_device_set_power() is called
during device removal.  Moreover, device initialization may depend on
setting device power states properly.

For these reasons, make the routines manipulating ACPI device power
states defined in drivers/acpi/device_pm.c available for CONFIG_PM
unset too.

Reported-by: Zhang Rui <rui.zhang@intel.com>
Reported-and-tested-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 3.9+ <stable@vger.kernel.org>
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 98db31d9..636c59f 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -377,7 +377,6 @@
 				       unsigned long long *sta);
 int acpi_bus_get_status(struct acpi_device *device);
 
-#ifdef CONFIG_PM
 int acpi_bus_set_power(acpi_handle handle, int state);
 const char *acpi_power_state_string(int state);
 int acpi_device_get_power(struct acpi_device *device, int *state);
@@ -385,41 +384,12 @@
 int acpi_bus_init_power(struct acpi_device *device);
 int acpi_bus_update_power(acpi_handle handle, int *state_p);
 bool acpi_bus_power_manageable(acpi_handle handle);
+
+#ifdef CONFIG_PM
 bool acpi_bus_can_wakeup(acpi_handle handle);
-#else /* !CONFIG_PM */
-static inline int acpi_bus_set_power(acpi_handle handle, int state)
-{
-	return 0;
-}
-static inline const char *acpi_power_state_string(int state)
-{
-	return "D0";
-}
-static inline int acpi_device_get_power(struct acpi_device *device, int *state)
-{
-	return 0;
-}
-static inline int acpi_device_set_power(struct acpi_device *device, int state)
-{
-	return 0;
-}
-static inline int acpi_bus_init_power(struct acpi_device *device)
-{
-	return 0;
-}
-static inline int acpi_bus_update_power(acpi_handle handle, int *state_p)
-{
-	return 0;
-}
-static inline bool acpi_bus_power_manageable(acpi_handle handle)
-{
-	return false;
-}
-static inline bool acpi_bus_can_wakeup(acpi_handle handle)
-{
-	return false;
-}
-#endif /* !CONFIG_PM */
+#else
+static inline bool acpi_bus_can_wakeup(acpi_handle handle) { return false; }
+#endif
 
 #ifdef CONFIG_ACPI_PROC_EVENT
 int acpi_bus_generate_proc_event(struct acpi_device *device, u8 type, int data);