wil6210: Provide signal strength indication

When notifying about Rx mgmt (ex: during scan), extract
signal strength reported by the hardware.
signal is not MBM, it is arbitrary units 0..100

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --cc drivers/net/wireless/ath/wil6210/cfg80211.c
Simple merge

diff --cc drivers/net/wireless/ath/wil6210/wmi.c
Simple merge