[RTT2] Fix preamble configuration to support 5GHz bandwidth < 80MHz

Incorrect preamble setting was used for BW 5GHz but bandwidth < 80MHz.

Bug: 68936111
Test: unit test & integration test (but only with 80MHz bw AP)
Change-Id: If572dcaf59b35b9759d819650946c1c8b97a8586
1 file changed