wifi: nl80211: Split memcpy() of struct nl80211_wowlan_tcp_data_token flexible array

To work around a misbehavior of the compiler's ability to see into
composite flexible array structs (as detailed in the coming memcpy()
hardening series[1]), split the memcpy() of the header and the payload
so no false positive run-time overflow warning will be generated.

[1] https://lore.kernel.org/linux-hardening/20220901065914.1417829-2-keescook@chromium.org/Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/nl80211.c

@@ -13265,7 +13265,9 @@ static int nl80211_parse_wowlan_tcp(struct cfg80211_registered_device *rdev,
 	       wake_mask_size);
 	if (tok) {
 		cfg->tokens_size = tokens_size;
-		memcpy(&cfg->payload_tok, tok, sizeof(*tok) + tokens_size);
+		cfg->payload_tok = *tok;
+		memcpy(cfg->payload_tok.token_stream, tok->token_stream,
+		       tokens_size);
 	}
 
 	trig->tcp = cfg;