ath10k: fix updating peer stats rx duration

We are not updating peer stats rx_duration periodically
unless the user one polls for fw_stats, this is because
we discard the update event since pdev list is empty. Fix
this by updating rx duration periodically irrepective of checks
for pdev list (irrespective of ping-pong response)

Fixes: 856e7c30 ("ath10k: add debugfs support for Per STA total rx duration")
Signed-off-by: Mohammed Shafi Shajakhan <mohammed@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>