nl80211: Remove QCA vendor specific HE capability handling

nl80211: Remove QCA vendor specific HE capability handling

The QCA_NL80211_VENDOR_SUBCMD_GET_HE_CAPABILITIES attributes are not
up-to-date with the latest P802.11ax/D4.0 capabilities and would need to
be updated or replaced. Since the variables from this functionality were
not used for anything in practice, it is easier to simply remove this
functionality completely to avoid issues with upcoming updates to use
upstream nl80211 information to determine HE capabilities.

This is practically reverting the commit ca1ab9db2a9e ("hostapd: Get
vendor HE capabilities").

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