BACKPORT: FROMGIT: virt_wifi: Return micros for BSS TSF values

cfg80211_inform_bss expects to receive a TSF value, but is given the
time since boot in nanoseconds. TSF values are expected to be at
microsecond scale rather than nanosecond scale.

Bug: 181840234
Test: atest CtsWifiTestCases:android.net.wifi.cts.ScanResultTest#testScanResultTimeStamp -- --abi x86_64
Signed-off-by: A. Cody Schuffelen <schuffelen@google.com>
Link: https://lore.kernel.org/r/20210318200419.1421034-1-schuffelen@google.com


Signed-off-by: Johannes Berg <johannes.berg@intel.com>
(cherry picked from commit b57aa17f07c9270e576ef7df09f142978b5a75f0
https: //git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git master)
Change-Id: Icafc24ad303357926cbe955ffa12e28e0bf31e6f