rtw88/rtw89: add module_param to enable/disable HT/VHT and EHT

In order to better test HT and VHT support with LinuxKPI add (tunable)
options disabled by default to on-demand enable HT/VHT
and for rtw89 also EHT.

It is expected that we will remove this FreeBSD-specific code again in
the future.

Sponsored by: The FreeBSD Foundation
MFC after: 3 days