wil6210: fix PCIe bus mastering in case of interface down

In case of interface down, radio is turned off but PCIe mastering is
not cleared.
This can cause unexpected PCIe access to the shutdown device.
Fix this by clearing PCIe mastering also in case interface is down

Change-Id: Iaf7ce20f99d25ab8a330b470c1b73956748f1d84
Signed-off-by: Lazar Alexei <qca_ailizaro@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
Git-commit: 680c242dc25e036265793edc7d755cfc15afd231
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/kvalo/ath.git


Signed-off-by: Maya Erez <merez@codeaurora.org>