wifi: rtl8xxxu: use swap() in rtl8xxxu_switch_ports()

Use existing swap() function rather than duplicating its implementation.

./drivers/net/wireless/realtek/rtl8xxxu/core.c:6749:30-31: WARNING opportunity for swap().
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=9358Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20240619024017.53246-1-jiapeng.chong@linux.alibaba.com

drivers/net/wireless/realtek/rtl8xxxu/core.c

@@ -6679,7 +6679,6 @@ static void rtl8xxxu_switch_ports(struct rtl8xxxu_priv *priv)
 	u8 macid[ETH_ALEN], bssid[ETH_ALEN], macid_1[ETH_ALEN], bssid_1[ETH_ALEN];
 	u8 msr, bcn_ctrl, bcn_ctrl_1, atimwnd[2], atimwnd_1[2];
 	struct rtl8xxxu_vif *rtlvif;
-	struct ieee80211_vif *vif;
 	u8 tsftr[8], tsftr_1[8];
 	int i;
 
@@ -6744,10 +6743,7 @@ static void rtl8xxxu_switch_ports(struct rtl8xxxu_priv *priv)
 	/* write bcn ctl */
 	rtl8xxxu_write8(priv, REG_BEACON_CTRL, bcn_ctrl_1);
 	rtl8xxxu_write8(priv, REG_BEACON_CTRL_1, bcn_ctrl);
-
-	vif = priv->vifs[0];
-	priv->vifs[0] = priv->vifs[1];
-	priv->vifs[1] = vif;
+	swap(priv->vifs[0], priv->vifs[1]);
 
 	/* priv->vifs[0] is NULL here, based on how this function is currently
 	 * called from rtl8xxxu_add_interface().