platform / x86 / PM: Fix unused function warnings for CONFIG_PM_SLEEP

According to compiler warnings, quite some suspend/resume functions
in platform x86 drivers are not used for CONFIG_PM_SLEEP unset, so
add #ifdefs to prevent them from being built in that case.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/drivers/platform/x86/toshiba_acpi.c b/drivers/platform/x86/toshiba_acpi.c
index c13ba5b..5f1256d 100644
--- a/drivers/platform/x86/toshiba_acpi.c
+++ b/drivers/platform/x86/toshiba_acpi.c
@@ -1296,6 +1296,7 @@
 	}
 }
 
+#ifdef CONFIG_PM_SLEEP
 static int toshiba_acpi_suspend(struct device *device)
 {
 	struct toshiba_acpi_dev *dev = acpi_driver_data(to_acpi_device(device));
@@ -1317,6 +1318,7 @@
 
 	return 0;
 }
+#endif
 
 static SIMPLE_DEV_PM_OPS(toshiba_acpi_pm,
 			 toshiba_acpi_suspend, toshiba_acpi_resume);