WNM: Extend workaround for broken AP operating class behavior

WNM: Extend workaround for broken AP operating class behavior

Some APs do not advertise operating classes correctly for BSS Transition
Management. Try to determine the most likely operating frequency based
on the channel number (1..14 --> 2.4 GHz; 36..177 --> 5 GHz) if invalid
op_class == 255 is received in a BSS Transition Management Request. This
speeds up the following operating by avoiding a full scan due to an
unknown channel.

This extends the workaround that was added in commit 80ce804e8824 ("WNM:
Workaround for broken AP operating class behavior") for invalid
operating class 0 to cover another observed case with invalid operating
class 255.

Signed-off-by: Yu Zhang(Yuriy) <quic_yuzha@quicinc.com>