wireless: cw1200: use __maybe_unused to hide pm functions_

The cw1200 uses #ifdef to check for CONFIG_PM, but then
uses SIMPLE_DEV_PM_OPS, which leaves the references out when
CONFIG_PM_SLEEP is not defined, so we get a warning with
PM=y && PM_SLEEP=n:

drivers/net/wireless/st/cw1200/cw1200_spi.c:450:12: error: 'cw1200_spi_suspend' defined but not used [-Werror=unused-function]

This removes the incorrect #ifdef and instead uses a __maybe_unused
annotation to let the compiler know it can silently drop
the function definition.

For the DEV_PM_OPS definition, we can use an IS_ENABLED() check
to avoid defining the structure when CONFIG_PM is not set without
the #ifdef.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/st/cw1200/cw1200_spi.c

@@ -446,8 +446,7 @@ static int cw1200_spi_disconnect(struct spi_device *func)
 	return 0;
 }
 
-#ifdef CONFIG_PM
-static int cw1200_spi_suspend(struct device *dev)
+static int __maybe_unused cw1200_spi_suspend(struct device *dev)
 {
 	struct hwbus_priv *self = spi_get_drvdata(to_spi_device(dev));
 
@@ -460,16 +459,12 @@ static int cw1200_spi_suspend(struct device *dev)
 
 static SIMPLE_DEV_PM_OPS(cw1200_pm_ops, cw1200_spi_suspend, NULL);
 
-#endif
-
 static struct spi_driver spi_driver = {
 	.probe		= cw1200_spi_probe,
 	.remove		= cw1200_spi_disconnect,
 	.driver = {
 		.name		= "cw1200_wlan_spi",
-#ifdef CONFIG_PM
-		.pm		= &cw1200_pm_ops,
-#endif
+		.pm		= IS_ENABLED(CONFIG_PM) ? &cw1200_pm_ops : NULL,
 	},
 };
 

drivers/net/wireless/st/cw1200/pm.h

@@ -31,13 +31,18 @@ int cw1200_pm_init(struct cw1200_pm_state *pm,
 void cw1200_pm_deinit(struct cw1200_pm_state *pm);
 int cw1200_wow_suspend(struct ieee80211_hw *hw,
 		       struct cfg80211_wowlan *wowlan);
-int cw1200_wow_resume(struct ieee80211_hw *hw);
 int cw1200_can_suspend(struct cw1200_common *priv);
+int cw1200_wow_resume(struct ieee80211_hw *hw);
 void cw1200_pm_stay_awake(struct cw1200_pm_state *pm,
 			  unsigned long tmo);
 #else
 static inline void cw1200_pm_stay_awake(struct cw1200_pm_state *pm,
-					unsigned long tmo) {
+					unsigned long tmo)
+{
+}
+static inline int cw1200_can_suspend(struct cw1200_common *priv)
+{
+	return 0;
 }
 #endif
 #endif