wil6210: notify cfg80211_new_sta upon connection before init tx ring

In AP mode upon client connection, sometimes Rx data packet
(e.g EAPOL) arrives before driver notify cfg80211_new_sta to kernel.
This causes the Rx packet to get lost.
To fix this, as part of connect event handling,
call cfg80211_new_sta() earlier, before initializing Tx ring.

Change-Id: Ife5fd7a5c79da4c0dd094c2b9cbc3785a165331d
Signed-off-by: Alexei Avshalom Lazar <ailizaro@codeaurora.org>