Fill the current opclass in (Re)AssocRequest depending on HT/VHT IEs

Fill the current opclass in (Re)AssocRequest depending on HT/VHT IEs

The previous implementation was assuming a fixed 20 MHz channel
bandwidth when determining which operating class value to indicate as
the Current Operating Class in the Supported Operating Classes element.
This is not accurate for many HT/VHT cases.

Fix this by determining the current operating class (i.e., the operating
class used for the requested association) based on the HT/VHT operation
elements from scan results.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>