wifi: cfg80211: silence a sparse RCU warning

stable inclusion
from stable-v5.10.155
commit 914cb94e738ba6ebb482d61567fb50bf700e4f19
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7M5F4

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=914cb94e738ba6ebb482d61567fb50bf700e4f19



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[ Upstream commit 03c0ad4b ]

All we're going to do with this pointer is assign it to
another __rcu pointer, but sparse can't see that, so
use rcu_access_pointer() to silence the warning here.

Fixes: c90b93b5 ("wifi: cfg80211: update hidden BSSes to avoid WARN_ON")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>