wifi: cfg80211: add support for advertising multiple radios belonging to a wiphy

wifi: cfg80211: add support for advertising multiple radios belonging to a wiphy

The prerequisite for MLO support in cfg80211/mac80211 is that all the links
participating in MLO must be from the same wiphy/ieee80211_hw. To meet this
expectation, some drivers may need to group multiple discrete hardware each
acting as a link in MLO under single wiphy.

With this change, supported frequencies and interface combinations of each
individual radio are reported to user space. This allows user space to figure
out the limitations of what combination of channels can be used concurrently.

Even for non-MLO devices, this improves support for devices capable of
running on multiple channels at the same time.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://patch.msgid.link/18a88f9ce82b1c9f7c12f1672430eaf2bb0be295.1720514221.git-series.nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>