wifi: mac80211_hwsim: split iftype data into AP/non-AP

The next patch will require splitting the data here into
AP and non-AP because for EHT, the format of the MCS/NSS
support (struct ieee80211_eht_mcs_nss_supp) is different,
for AP the only_20mhz cannot be used.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>