wifi: cfg80211: Add parameters to radio-specific debugfs directories

wifi: cfg80211: Add parameters to radio-specific debugfs directories

In multi-radio wiphy architecture, where a single wiphy can have
multiple radios tied to it, radio specific configuration parameters
and global wiphy parameters are maintained for the entire physical
device and common to all radios. But, each radio in a wiphy can
have different values for each radio configuration parameter like
RTS threshold. With the current debugfs directory structure, the
values of global wiphy configuration parameters can be viewed, but,
values of individual radio configuration parameters cannot be viewed.

To address this requirement, maintain separate entries of each radio
configuration parameter i.e., RTS threshold in corresponding radio-
specific debugfs directory. This way, radio-specific configuration
parameters can be maintained along with global wiphy configuration
parameters. Whenever the values are changed for one radio, the values
for rest of the radios in the wiphy and the global wiphy parameter
value will remain intact.

Sample output:
/# iw phy#0 set rts 100 radio 1
/# iw phy#0 set rts 468 radio 0
/# cat /sys/kernel/debug/ieee80211/phy0/rts_threshold
-1
/# cat /sys/kernel/debug/ieee80211/phy0/radio0/radio_rts_threshold
468
/# cat /sys/kernel/debug/ieee80211/phy0/radio1/radio_rts_threshold
100

/# iw phy#0 set rts 500
/# cat /sys/kernel/debug/ieee80211/phy0/rts_threshold
500
/# cat /sys/kernel/debug/ieee80211/phy0/radio0/radio_rts_threshold
500
/# cat /sys/kernel/debug/ieee80211/phy0/radio1/radio_rts_threshold
500

Signed-off-by: Roopni Devanathan <quic_rdevanat@quicinc.com>
Link: https://patch.msgid.link/20251024044649.483557-3-quic_rdevanat@quicinc.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>