wifi: mac80211: determine missing link_id in ieee80211_rx_for_interface() based on frequency

For broadcast frames, every interface might have to process it and
therefore the link_id cannot be determined in the driver.

In mac80211, when the frame is about to be forwarded to each interface,
we can use the member "freq" in struct ieee80211_rx_status to determine
the "link_id" for each interface.

Signed-off-by: Michael-CY Lee <michael-cy.lee@mediatek.com>
Reviewed-by: Money Wang <money.wang@mediatek.com>
Link: https://patch.msgid.link/20250721062929.1662700-1-michael-cy.lee@mediatek.com


[simplify, remove unnecessary link->conf check]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>