Staging: gdm72xx: silence underflow warning in netlink_send()

The value of "group" comes from "idx" in __gdm_wimax_event_send():

	if (sscanf(e->dev->name, "wm%d", &idx) == 1)

Smatch marks sscanf values as user controlled.  It's supposed to be a
number in 0-30 range.  We cap the upper bound but allow negatives.  Fix
this by making it type u16 instead.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/gdm72xx/netlink_k.c

@@ -114,7 +114,7 @@ void netlink_exit(struct sock *sock)
 	netlink_kernel_release(sock);
 }
 
-int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len)
+int netlink_send(struct sock *sock, u16 group, u16 type, void *msg, int len)
 {
 	static u32 seq;
 	struct sk_buff *skb = NULL;

drivers/staging/gdm72xx/netlink_k.h

@@ -20,6 +20,6 @@
 struct sock *netlink_init(int unit, void (*cb)(struct net_device *dev, u16 type,
 					       void *msg, int len));
 void netlink_exit(struct sock *sock);
-int netlink_send(struct sock *sock, int group, u16 type, void *msg, int len);
+int netlink_send(struct sock *sock, u16 group, u16 type, void *msg, int len);
 
 #endif /* __GDM72XX_NETLINK_K_H__ */