staging: rtl8192u: Fixes symbol as static

This patch fixes "symbol 'ieee80211_send_probe_requests_rsl'
was not declared. Should it be static?" sparse warning
in ieee80211_softmac.c
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c

@@ -411,7 +411,7 @@ static void ieee80211_send_probe(struct ieee80211_device *ieee)
 	}
 }
 
-void ieee80211_send_probe_requests(struct ieee80211_device *ieee)
+static void ieee80211_send_probe_requests(struct ieee80211_device *ieee)
 {
 	if (ieee->active_scan && (ieee->softmac_features & IEEE_SOFTMAC_PROBERQ)){
 		ieee80211_send_probe(ieee);