staging: rtl8192u: Fix big-endian warning

When compiling the rtl8192u driver from staging on a big-endian
architecture, the following warning results:

  CC [M]  drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.o
drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c: In function 'ieee80211_probe_resp':
drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c:780: warning: value computed is not used

The warning is due to misuse of cpu_to_le16().
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/rtl8192u/ieee80211/ieee80211_softmac.c

@@ -776,7 +776,7 @@ static struct sk_buff* ieee80211_probe_resp(struct ieee80211_device *ieee, u8 *d
 		cpu_to_le16(ieee->current_network.capability & WLAN_CAPABILITY_SHORT_PREAMBLE); //add short preamble here
 
 	if(ieee->short_slot && (ieee->current_network.capability & WLAN_CAPABILITY_SHORT_SLOT))
-		cpu_to_le16((beacon_buf->capability |= WLAN_CAPABILITY_SHORT_SLOT));
+		beacon_buf->capability |= cpu_to_le16(WLAN_CAPABILITY_SHORT_SLOT);
 
 	crypt = ieee->crypt[ieee->tx_keyidx];
 	if (encrypt)