tboot: Add return values for tboot_sleep

.. as appropiately. As tboot_sleep now returns values.
remove tboot_sleep_wrapper.
Suggested-and-Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Joseph Cihula <joseph.cihula@intel.com>
[v1: Return -1/0/+1 instead of ACPI_xx values]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

arch/x86/kernel/tboot.c

@@ -272,7 +272,7 @@ static void tboot_copy_fadt(const struct acpi_table_fadt *fadt)
 		offsetof(struct acpi_table_facs, firmware_waking_vector);
 }
 
-void tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
+static int tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
 {
 	static u32 acpi_shutdown_map[ACPI_S_STATE_COUNT] = {
 		/* S0,1,2: */ -1, -1, -1,
@@ -281,7 +281,7 @@ void tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
 		/* S5: */ TB_SHUTDOWN_S5 };
 
 	if (!tboot_enabled())
-		return;
+		return 0;
 
 	tboot_copy_fadt(&acpi_gbl_FADT);
 	tboot->acpi_sinfo.pm1a_cnt_val = pm1a_control;
@@ -292,15 +292,10 @@ void tboot_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control)
 	if (sleep_state >= ACPI_S_STATE_COUNT ||
 	    acpi_shutdown_map[sleep_state] == -1) {
 		pr_warning("unsupported sleep state 0x%x\n", sleep_state);
-		return;
+		return -1;
 	}
 
 	tboot_shutdown(acpi_shutdown_map[sleep_state]);
-}
-static int tboot_sleep_wrapper(u8 sleep_state, u32 pm1a_control,
-			       u32 pm1b_control)
-{
-	tboot_sleep(sleep_state, pm1a_control, pm1b_control);
 	return 0;
 }
 
@@ -352,7 +347,7 @@ static __init int tboot_late_init(void)
 	atomic_set(&ap_wfs_count, 0);
 	register_hotcpu_notifier(&tboot_cpu_notifier);
 
-	acpi_os_set_prepare_sleep(&tboot_sleep_wrapper);
+	acpi_os_set_prepare_sleep(&tboot_sleep);
 	return 0;
 }