wifi: mac80211: add flag to opt out of virtual monitor support

This is useful for multi-radio devices that are capable of monitoring on
multiple channels simultanenously. When this flag is set, each monitor
interface is passed to the driver individually and can have a configured
channel.
The vif mac address for non-active monitor interfaces is cleared, in order
to allow the driver to tell them apart from active ones.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://patch.msgid.link/3c55505ee0cf0a5f141fbcb30d1e8be8d9f40373.1728462320.git-series.nbd@nbd.name


Signed-off-by: Johannes Berg <johannes.berg@intel.com>