wifi: mac80211: Allow DFS/CSA on a radio if scan is ongoing on another radio

wifi: mac80211: Allow DFS/CSA on a radio if scan is ongoing on another radio

Currently, in multi-radio wiphy cases, if a scan is ongoing on one radio,
-EBUSY is returned when DFS or a channel switch is initiated on another
radio. Because of this, an MLD AP with one radio (link) in an ongoing scan
cannot initiate DFS or a channel switch on another radio (link).

In multi-radio wiphy cases, multiple radios are grouped under a single
wiphy. Hence, if a scan is ongoing on one underlying radio and DFS or a
channel switch is requested on a different underlying radio of the same
wiphy, these operations can be allowed simultaneously.

Add logic to check the underlying radio used for the ongoing scan. If the
radio on which DFS or a channel switch is requested is not being used for
the scan, allow the operation; otherwise, return -EBUSY.

Signed-off-by: Aditya Kumar Singh <aditya.kumar.singh@oss.qualcomm.com>
Co-developed-by: Raj Kumar Bhagat <quic_rajkbhag@quicinc.com>
Signed-off-by: Raj Kumar Bhagat <quic_rajkbhag@quicinc.com>
Link: https://patch.msgid.link/20250527-mlo-dfs-acs-v2-2-92c2f37c81d9@quicinc.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>