Currently there is no ini support to configure frequencies
which needs to be avoided for the acs channel list which
may allow SAP to come up on a channel which is not preferred.
For Example there are many legacy clients which supports
2.4GHz but don't support channel 12 and 13 (or does not have
the capability to detect country change where channel 12 and
13 is valid).
In that case, if SAP comes up on channel 12/13, those legacy
clients won't be able to connect to AP.
Hence, Add a feature flag and ini to configure the frequency
list which can be avoided during acs.
Change-Id: Id106b38228f837ba056eb916004dc012e919ddd2
CRs-Fixed: 2472004
2168aadfa4