ACPI: Print message before calling _PTS

Make acpi_sleep_prepare() static and cause it to print a message
specifying the ACPI system sleep state to be entered (helpful for
debugging the suspend/hibernation code).

Signed-off-by: Rafael J. Wysocki <[e-mail]>
Acked-by: Pavel Machek <[e-mail]>
Signed-off-by: Len Brown <[e-mail]>

drivers/acpi/sleep/main.c

···
 __setup("acpi_new_pts_ordering", acpi_new_pts_ordering);
 #endif
 
-int acpi_sleep_prepare(u32 acpi_state)
+static int acpi_sleep_prepare(u32 acpi_state)
 {
 #ifdef CONFIG_ACPI_SLEEP
 	/* do we have a wakeup address for S2 and S3? */
···
 	ACPI_FLUSH_CPU_CACHE();
 	acpi_enable_wakeup_device_prep(acpi_state);
 #endif
+	printk(KERN_INFO PREFIX "Preparing to enter system sleep state S%d\n",
+		acpi_state);
 	acpi_enter_sleep_state_prep(acpi_state);
 	return 0;
 }

drivers/acpi/sleep/sleep.h

···
 extern void acpi_enable_wakeup_device_prep(u8 sleep_state);
 extern void acpi_enable_wakeup_device(u8 sleep_state);
 extern void acpi_disable_wakeup_device(u8 sleep_state);
-
-extern int acpi_sleep_prepare(u32 acpi_state);