Staging: brcm80211: make interface name buffer smaller

In the original code the interface name was IFNAMSIZ + 1, but that
caused problems in dhd_ifname2idx() which does:
	strncmp(dhd->iflist[i]->name, name, IFNAMSIZ)

The wl_event_msg_t struct can only store 16 character names as well.

And thirdly there is a potential buffer overflow in dhd_op_if() because
if->net->name is IFNAMSIZ and we do:
	strcpy(ifp->net->name, ifp->name);

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>