staging: vt6656: vnt_beacon_xmit use extra_tx_headroom.

Create room for vnt_tx_short_buf_head in sk_buff and vnt_tx_usb_header.

The struct ieee80211_mgmt is not longer in the header and is at
the initial skb->data point.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/5f00d319-9242-65b2-d100-dcfe9b0e32be@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>