cfg80211: don't allow WoWLAN support without CONFIG_PM

When CONFIG_PM is disabled, no device can possibly
support WoWLAN since it can't go to sleep to start
with. Due to this, mac80211 had even rejected the
hardware registration. By making all the code and
data for WoWLAN depend on CONFIG_PM we can promote
this runtime error to a compile-time error.

Add #ifdef around all WoWLAN code to remove it in
systems that don't need it as they never suspend.

Cc: Kalle Valo <kvalo@qca.qualcomm.com>
Acked-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/net/cfg80211.h

@@ -2153,7 +2153,9 @@ struct wiphy {
 	char fw_version[ETHTOOL_BUSINFO_LEN];
 	u32 hw_version;
 
+#ifdef CONFIG_PM
 	struct wiphy_wowlan_support wowlan;
+#endif
 
 	u16 max_remain_on_channel_duration;