mwifiex: add auto TDLS support

This patch adds auto TDLS support to mwifiex.

Auto TDLS functionality works as follows:
1. Whenever userspace application has triggered TDLS connection with
any peer, driver would store this peer mac address details in its database.
2. After this driver whenever driver receives packet on direct link,
it would store rssi and timestamp in peer information.
3. Whenever a packet is to be transmitted to non-AP peer in station mode,
driver would check if TDLS link can be established by looking at peer RSSI
information. Driver would initiate TDLS setup in such cases.
4. Periodic timer is used for updating peer information.
5. Auto TDLS peer list & timer are cleared during disconnection or driver unload.

Signed-off-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Cathy Luo <cluo@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>