staging: gdm724x: fix return codes in gdm_lte

fix return codes in gdm_lte in gdm724x driver
Signed-off-by: Andrii Vladyka <tulup@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/gdm724x/gdm_lte.c

@@ -246,13 +246,13 @@ static int gdm_lte_emulate_ndp(struct sk_buff *skb_in, u32 nic_type)
 	if (ntohs(((struct ethhdr *)skb_in->data)->h_proto) == ETH_P_8021Q) {
 		memcpy(&vlan_eth, skb_in->data, sizeof(struct vlan_ethhdr));
 		if (ntohs(vlan_eth.h_vlan_encapsulated_proto) != ETH_P_IPV6)
-			return -1;
+			return -EPROTONOSUPPORT;
 		mac_header_data = &vlan_eth;
 		mac_header_len = VLAN_ETH_HLEN;
 	} else {
 		memcpy(&eth, skb_in->data, sizeof(struct ethhdr));
 		if (ntohs(eth.h_proto) != ETH_P_IPV6)
-			return -1;
+			return -EPROTONOSUPPORT;
 		mac_header_data = ð
 		mac_header_len = ETH_HLEN;
 	}
@@ -260,13 +260,13 @@ static int gdm_lte_emulate_ndp(struct sk_buff *skb_in, u32 nic_type)
 	/* Check if this is IPv6 ICMP packet */
 	ipv6_in = (struct ipv6hdr *)(skb_in->data + mac_header_len);
 	if (ipv6_in->version != 6 || ipv6_in->nexthdr != IPPROTO_ICMPV6)
-		return -1;
+		return -EPROTONOSUPPORT;
 
 	/* Check if this is NDP packet */
 	icmp6_in = (struct icmp6hdr *)(skb_in->data + mac_header_len +
 					sizeof(struct ipv6hdr));
 	if (icmp6_in->icmp6_type == NDISC_ROUTER_SOLICITATION) { /* Check RS */
-		return -1;
+		return -EPROTONOSUPPORT;
 	} else if (icmp6_in->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION) {
 		/* Check NS */
 		u8 icmp_na[sizeof(struct icmp6hdr) +
@@ -310,7 +310,7 @@ static int gdm_lte_emulate_ndp(struct sk_buff *skb_in, u32 nic_type)
 		icmp6_out.icmp6_cksum = icmp6_checksum(&ipv6_out,
 					(u16 *)icmp_na, sizeof(icmp_na));
 	} else {
-		return -1;
+		return -EINVAL;
 	}
 
 	/* Fill the destination mac with source mac of the received packet */
@@ -417,7 +417,7 @@ static int gdm_lte_tx(struct sk_buff *skb, struct net_device *dev)
 	nic_type = gdm_lte_tx_nic_type(dev, skb);
 	if (nic_type == 0) {
 		netdev_err(dev, "tx - invalid nic_type\n");
-		return -1;
+		return -EMEDIUMTYPE;
 	}
 
 	if (nic_type & NIC_TYPE_ARP) {
@@ -544,7 +544,7 @@ int gdm_lte_event_init(void)
 	}
 
 	pr_err("event init failed\n");
-	return -1;
+	return -ENODATA;
 }
 
 void gdm_lte_event_exit(void)