wifi: mac80211: set link ID in TX info for beacons

This is simple here, and might save drivers some work if
they have common code for TX between beacons and other
frames.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/tx.c

@@ -5097,6 +5097,8 @@ ieee80211_beacon_get_finish(struct ieee80211_hw *hw,
 	rate_control_get_rate(sdata, NULL, &txrc);
 
 	info->control.vif = vif;
+	info->control.flags |= u32_encode_bits(link->link_id,
+					       IEEE80211_TX_CTRL_MLO_LINK);
 	info->flags |= IEEE80211_TX_CTL_CLEAR_PS_FILT |
 		       IEEE80211_TX_CTL_ASSIGN_SEQ |
 		       IEEE80211_TX_CTL_FIRST_FRAGMENT;