[PATCH] acpi_shutdown: Only prepare for power off on power_off

When acpi_sleep_prepare was moved into a shutdown method we
started calling it for all shutdowns.

It appears this triggers some systems to power off on reboot.

Avoid this by only calling acpi_sleep_prepare if we are going to power
off the system.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/acpi/sleep/poweroff.c

@@ -55,7 +55,11 @@ void acpi_power_off(void)
 
 static int acpi_shutdown(struct sys_device *x)
 {
+	if (system_state == SYSTEM_POWER_OFF) {
+		/* Prepare if we are going to power off the system */
 		return acpi_sleep_prepare(ACPI_STATE_S5);
+	}
+	return 0;
 }
 
 static struct sysdev_class acpi_sysclass = {