nl80211: Add per peer statistics to compute FCS error rate

nl80211: Add per peer statistics to compute FCS error rate

Add support for drivers to report the total number of MPDUs received
and the number of MPDUs received with an FCS error from a specific
peer. These counters will be incremented only when the TA of the
frame matches the MAC address of the peer irrespective of FCS
error.

It should be noted that the TA field in the frame might be corrupted
when there is an FCS error and TA matching logic would fail in such
cases. Hence, FCS error counter might not be fully accurate, but it can
provide help in detecting bad RX links in significant number of cases.
This FCS error counter without full accuracy can be used, e.g., to
trigger a kick-out of a connected client with a bad link in AP mode to
force such a client to roam to another AP.

Signed-off-by: Ankita Bajaj <bankita@codeaurora.org>
Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>