HE/VHT: Fix frequency setup with HE enabled

HE/VHT: Fix frequency setup with HE enabled

Some places in the code base were not using the wrappers like
hostapd_set_oper_centr_freq_seg0_idx and friends. This could lead to
errors, for example when joining 80 MHz mesh networks. Fix this, by
enforcing usage of these wrappers.

wpa_supplicant_conf_ap_ht() now checks for HE capability before dealing
with VHT in order for these wrappers to work, as they first check HE
support in the config.

While doing these changes, I've noticed that the extra channel setup
code for mesh networks in wpa_supplicant/mesh.c should not be necessary
anymore and dropped it. wpa_supplicant_conf_ap_ht() should handle this
setup already.

Acked-by: John Crispin <john@phrozen.org>
Signed-off-by: Markus Theil <markus.theil@tu-ilmenau.de>