[WCNCR00146539] softap: Fix TGn 4.2.44 and 4.2.45 softap cert fail items

[Description]
Fix TGn 4.2.44 and 4.2.45 softap cert fail items
1. no HT cap and op IE in BCN with WEP mode
2. disallow TKIP with HT Rates to meet cert requirement
3. Clean the beacon update message buffer after allocated
   to avoid unexpected content.

Change-Id: I348e1946cf191a11b811ecd7a8f1977a32282100
Signed-off-by: Awk Jiang <awk.jiang@mediatek.com>
CR-Id: WCNCR00146539
Feature: softap
8 files changed