wifi: rtw89: pass target link_id to ieee80211_nullfunc_get()

When calling ieee80211_nullfunc_get(), pass the target link_id
instead of always -1.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Link: https://patch.msgid.link/20241120034054.13575-7-pkshih@realtek.com