Wifi: Consider the current configured band while calculating the visibility.

Auto Join controller needs the visibility of the networks to get the best
candidate to roam. The current API to calculate the visibility does not
consider the current configured band while looking for the SSID's.
This commit adds new API with configured band to retain existing API.

Change-Id: Ib5e2ad52f9af6d3c7740bb4a2737b06a234ea65b
CRs-Fixed: 797374