wifi: iwlwifi: mvm: check n_ssids before accessing the ssids

mainline inclusion
from mainline-v6.10-rc3
commit 60d62757df30b74bf397a2847a6db7385c6ee281
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IACZLE
CVE: CVE-2024-40929

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=60d62757df30b74bf397a2847a6db7385c6ee281



--------------------------------

In some versions of cfg80211, the ssids poinet might be a valid one even
though n_ssids is 0. Accessing the pointer in this case will cuase an
out-of-bound access. Fix this by checking n_ssids first.

Fixes: c1a75153 ("iwlwifi: mvm: add adaptive dwell support")
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Reviewed-by: Ilan Peer <ilan.peer@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Link: https://msgid.link/20240513132416.6e4d1762bf0d.I5a0e6cc8f02050a766db704d15594c61fe583d45@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Conflicts:
	drivers/net/wireless/intel/iwlwifi/mvm/scan.c
[The conflict occurs because the commit 19ff9b2c("iwlwifi: scan:
adapt the code to use api ver 11") is not merged]
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>