ACS: Add channels from all modes matching with configured hw mode

ACS: Add channels from all modes matching with configured hw mode

The 5 GHz channels are stored in one hw_features set with mode
HOSTAPD_MODE_IEEE80211A while the 6 GHz channels will need to stored in
a separate hw_features set (but with same mode HOSTAPD_MODE_IEEE80211A)
due to possibility of different HE capabilities being available between
the 5 GHz and 6 GHz bands.

Iterate through all hw_features sets and populate channels from all
hw_features sets whose hardware mode is matching the configured hardware
mode while preparing the channel list for ACS.

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