wil6210: increase PCP stop command timeout

In case there are connected stations, FW needs to disconnect
them before handling PCP stop. This flow can take several
seconds.
Increasing PCP stop timeout to 5 seconds to allow that.

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