mfd: rtsx: Fix build warnings for !PM

rtsx_pci_power_off() is called only from rtsx_pci_suspend(), which isn't
built when PM is disabled.
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/rtsx_pcr.c

@@ -947,6 +947,7 @@ static void rtsx_pci_idle_work(struct work_struct *work)
 	mutex_unlock(&pcr->pcr_mutex);
 }
 
+#ifdef CONFIG_PM
 static void rtsx_pci_power_off(struct rtsx_pcr *pcr, u8 pm_state)
 {
 	if (pcr->ops->turn_off_led)
@@ -961,6 +962,7 @@ static void rtsx_pci_power_off(struct rtsx_pcr *pcr, u8 pm_state)
 	if (pcr->ops->force_power_down)
 		pcr->ops->force_power_down(pcr, pm_state);
 }
+#endif
 
 static int rtsx_pci_init_hw(struct rtsx_pcr *pcr)
 {