cfg80211: Define nla_policy for NL80211_ATTR_LOCAL_MESH_POWER_MODE

Buffer overread may happen as nl80211_set_station() reads 4 bytes
from the attribute NL80211_ATTR_LOCAL_MESH_POWER_MODE without
validating the size of data received when userspace sends less
than 4 bytes of data with NL80211_ATTR_LOCAL_MESH_POWER_MODE.
Define nla_policy for NL80211_ATTR_LOCAL_MESH_POWER_MODE to avoid
the buffer overread.

Fixes: 3b1c5a53 ("{cfg,nl}80211: mesh power mode primitives and userspace access")
Cc: stable@vger.kernel.org
Signed-off-by: Srinivas Dasari <dasaris@qti.qualcomm.com>
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/jberg/mac80211.git


Git-commit: 8feb69c7bd89513be80eb19198d48f154b254021
Change-Id: Ie20993309501fd242782311b9fe787931f716116
CRs-Fixed: 2055013
Signed-off-by: Srinivas Dasari <dasaris@codeaurora.org>