wifi: mac80211: remove misleading j_0 construction parts

The GCM algorithm implementation in the kernel assumes that
a 12-byte IV is passed, not the actual J_0 from the GCM spec.
Don't rename, that'd be messy, but also don't fill the bytes
beyond the IV that aren't used, since otherwise it looks as
though j_0[12] is used uninitialized.

Link: https://patch.msgid.link/20241021151414.798ceb7a5896.Ic57751edad228d56865ecf7433fef469e5e0a4aa@changeid
Signed-off-by: Johannes Berg <[e-mail]>

net/mac80211/wpa.c

···
 
 	memcpy(j_0, hdr->addr2, ETH_ALEN);
 	memcpy(&j_0[ETH_ALEN], pn, IEEE80211_GCMP_PN_LEN);
-	j_0[13] = 0;
-	j_0[14] = 0;
-	j_0[AES_BLOCK_SIZE - 1] = 0x01;
 
 	ccmp_gcmp_aad(skb, aad, spp_amsdu);
 }