Add Nss and BW parsing after association.

Parse HT/VHT/HE capabilities and operation IE of association request
and response frames to get max_nss_rx, max_nss_tx and channel_bandwidth
capabilities of the current network.

This CL only includes changes to be upstreamed to wpa_supplicant and
doesn't include hidl change.

Bug: 147390882
Test: VTS test
Test: manual test with various APs.
Change-Id: Ie43aca62f7f02cb3c0862f7a36bc66fa5899191b
5 files changed