Handle join failure

In case join fails driver leaves hardware in joined state.
That will cause different side effects like next join will
always fail and scan does not work properly. As a fix just
delete bss  in case join failed.

Signed-off-by: Eugene Krasnikov <k.eugene.e@gmail.com>
Do not forget to remove sta in AP mode

In AP mode sometimes HW remained misconfigured because of
previous sta was not removed.

Signed-off-by: Eugene Krasnikov <k.eugene.e@gmail.com>
Do not encrypt EAPOL keys

Keys are coming in data frames. So do not encrypt
data packets until key exchange is finished.

Signed-off-by: Eugene Krasnikov <k.eugene.e@gmail.com>
Configure correct AID and sta_index in AP mode

Encrypted AP mode was not working because of misconfiguration.

Signed-off-by: Eugene Krasnikov <k.eugene.e@gmail.com>
Refactor TX path

With this patch all parameters will be first passed to txrx
module and only after that to dxe. This will allow passing
less parameters to the functions. Also make sure that data
frames will get as fast as possible to the HW.

Short function description:

wcn36xx_start_tx – fills in BD and trigger dxe to start
transmitting.

wcn36xx_fill_tx_pdu – fills is PDU part of BD.

wcn36xx_dxe_tx_frame – transmits one frame from the head
of the descriptors.

Signed-off-by: Eugene Krasnikov <k.eugene.e@gmail.com>