wifi: ath12k: fix one more memcpy size error

[ Upstream commit 19c23eb ]

A previous patch addressed a fortified-memcpy warning on older compilers,
but there is still a warning on gcc-14 in some configurations:

In file included from include/linux/string.h:390,
                 from drivers/net/wireless/ath/ath12k/wow.c:7:
drivers/net/wireless/ath/ath12k/wow.c: In function 'ath12k_wow_convert_8023_to_80211.isra':
include/linux/fortify-string.h:114:33: error: '__builtin_memcpy' accessing 18446744073709551610 or more bytes at offsets 0 and 0 overlaps 9223372036854775797 bytes at offset -9223372036854775803 [-Werror=restrict]
include/linux/fortify-string.h:679:26: note: in expansion of macro '__fortify_memcpy_chk'
  679 | #define memcpy(p, q, s)  __fortify_memcpy_chk(p, q, s,                  \
      |                          ^~~~~~~~~~~~~~~~~~~~
drivers/net/wireless/ath/ath12k/wow.c:199:25: note: in expansion of macro 'memcpy'
  199 |                         memcpy(pat + a3_ofs - pkt_ofs,
      |                         ^~~~~~

Address this the same way as the other two, using size_add().

Fixes: b49991d ("wifi: ath12k: fix build vs old compiler")
Fixes: 4a3c212 ("wifi: ath12k: add basic WoW functionalities")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kalle Valo <kvalo@kernel.org>
Link: https://patch.msgid.link/20241004095420.637091-1-arnd@kernel.org
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: arndb

drivers/net/wireless/ath/ath12k/wow.c

@@ -191,7 +191,7 @@ ath12k_wow_convert_8023_to_80211(struct ath12k *ar,
 			memcpy(bytemask, eth_bytemask, eth_pat_len);
 
 			pat_len = eth_pat_len;
-		} else if (eth_pkt_ofs + eth_pat_len < prot_ofs) {
+		} else if (size_add(eth_pkt_ofs, eth_pat_len) < prot_ofs) {
 			memcpy(pat, eth_pat, ETH_ALEN - eth_pkt_ofs);
 			memcpy(bytemask, eth_bytemask, ETH_ALEN - eth_pkt_ofs);