mac80211: Read rx_stats with perCPU pointers

Use perCPU pointers to get rx_stats in sta_set_sinfo
when RSS is enabled

Signed-off-by: Seevalamuthu Mariappan <seevalam@codeaurora.org>
Link: https://lore.kernel.org/r/1584526555-25960-1-git-send-email-seevalam@codeaurora.org


Signed-off-by: Johannes Berg <johannes.berg@intel.com>