wifi: ath10k: Use RMW accessors for changing LNKCTL

[ Upstream commit f139492a09f15254fa261245cdbd65555cdf39e3 ]

Don't assume that only the driver would be accessing LNKCTL. ASPM policy
changes can trigger write to LNKCTL outside of driver's control.

Use RMW capability accessors which does proper locking to avoid losing
concurrent updates to the register value. On restore, clear the ASPMC field
properly.

Suggested-by: Lukas Wunner <lukas@wunner.de>
Fixes: 76d870ed ("ath10k: enable ASPM")
Link: https://lore.kernel.org/r/20230717120503.15276-11-ilpo.jarvinen@linux.intel.com


Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Kalle Valo <kvalo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>