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/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index e7f7328..f28f36c 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -922,6 +922,7 @@
 static struct mutex tpacpi_inputdev_send_mutex;
 static LIST_HEAD(tpacpi_all_drivers);
 
+#ifdef CONFIG_PM_SLEEP
 static int tpacpi_suspend_handler(struct device *dev)
 {
 	struct ibm_struct *ibm, *itmp;
@@ -949,6 +950,7 @@
 
 	return 0;
 }
+#endif
 
 static SIMPLE_DEV_PM_OPS(tpacpi_pm,
 			 tpacpi_suspend_handler, tpacpi_resume_handler);