misc: rtsx: conditionally build rtsx_pm_power_saving()

BugLink: https://bugs.launchpad.net/bugs/1963615

On s390 allyesconfig, there is this build error
rtsx_pcr.c:1084:13: error: 'rtsx_pm_power_saving'
  defined but not used
 1084 | static void rtsx_pm_power_saving(struct rtsx_pcr *pcr)
      |             ^~~~~~~~~~~~~~~~~~~~

rtsx_pm_power_saving() is only used by rtsx_pci_runtime_idle()
which is conditional on CONFIG_PM.  So conditionally build
rtsx_pm_power_saving() and the similar
rtsx_comm_pm_power_saving() and rtsx_enable_aspm().

Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20220213171907.2786442-1-trix@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 2c9ae45 linux-next)
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Timo Aaltonen <timo.aaltonen@canonical.com>

drivers/misc/cardreader/rtsx_pcr.c

@@ -1054,38 +1054,6 @@ static int rtsx_pci_acquire_irq(struct rtsx_pcr *pcr)
 	return 0;
 }
 
-static void rtsx_enable_aspm(struct rtsx_pcr *pcr)
-{
-	if (pcr->ops->set_aspm)
-		pcr->ops->set_aspm(pcr, true);
-	else
-		rtsx_comm_set_aspm(pcr, true);
-}
-
-static void rtsx_comm_pm_power_saving(struct rtsx_pcr *pcr)
-{
-	struct rtsx_cr_option *option = &pcr->option;
-
-	if (option->ltr_enabled) {
-		u32 latency = option->ltr_l1off_latency;
-
-		if (rtsx_check_dev_flag(pcr, L1_SNOOZE_TEST_EN))
-			mdelay(option->l1_snooze_delay);
-
-		rtsx_set_ltr_latency(pcr, latency);
-	}
-
-	if (rtsx_check_dev_flag(pcr, LTR_L1SS_PWR_GATE_EN))
-		rtsx_set_l1off_sub_cfg_d0(pcr, 0);
-
-	rtsx_enable_aspm(pcr);
-}
-
-static void rtsx_pm_power_saving(struct rtsx_pcr *pcr)
-{
-	rtsx_comm_pm_power_saving(pcr);
-}
-
 static void rtsx_base_force_power_down(struct rtsx_pcr *pcr)
 {
 	/* Set relink_time to 0 */
@@ -1701,6 +1669,38 @@ static int __maybe_unused rtsx_pci_resume(struct device *dev_d)
 
 #ifdef CONFIG_PM
 
+static void rtsx_enable_aspm(struct rtsx_pcr *pcr)
+{
+	if (pcr->ops->set_aspm)
+		pcr->ops->set_aspm(pcr, true);
+	else
+		rtsx_comm_set_aspm(pcr, true);
+}
+
+static void rtsx_comm_pm_power_saving(struct rtsx_pcr *pcr)
+{
+	struct rtsx_cr_option *option = &pcr->option;
+
+	if (option->ltr_enabled) {
+		u32 latency = option->ltr_l1off_latency;
+
+		if (rtsx_check_dev_flag(pcr, L1_SNOOZE_TEST_EN))
+			mdelay(option->l1_snooze_delay);
+
+		rtsx_set_ltr_latency(pcr, latency);
+	}
+
+	if (rtsx_check_dev_flag(pcr, LTR_L1SS_PWR_GATE_EN))
+		rtsx_set_l1off_sub_cfg_d0(pcr, 0);
+
+	rtsx_enable_aspm(pcr);
+}
+
+static void rtsx_pm_power_saving(struct rtsx_pcr *pcr)
+{
+	rtsx_comm_pm_power_saving(pcr);
+}
+
 static void rtsx_pci_shutdown(struct pci_dev *pcidev)
 {
 	struct pcr_handle *handle = pci_get_drvdata(pcidev);