net: use symbolic values for ndo_start_xmit() return codes

Convert magic values 1 and -1 to NETDEV_TX_BUSY and NETDEV_TX_LOCKED respectively.

0 (NETDEV_TX_OK) is not changed to keep the noise down, except in very few cases
where its in direct proximity to one of the other values.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/wireless/hostap/hostap_80211_tx.c b/drivers/net/wireless/hostap/hostap_80211_tx.c
index 6693423..d313b00 100644
--- a/drivers/net/wireless/hostap/hostap_80211_tx.c
+++ b/drivers/net/wireless/hostap/hostap_80211_tx.c
@@ -377,7 +377,7 @@
 {
 	struct hostap_interface *iface;
 	local_info_t *local;
-	int ret = 1;
+	int ret = NETDEV_TX_BUSY;
 	u16 fc;
 	struct hostap_tx_data tx;
 	ap_tx_ret tx_ret;