wil6210: prevent device memory access while in reset or suspend

Accessing some of the memory of the device while the device is
resetting or suspending may cause unexpected error as the HW is still
not in a stable state. Prevent this access to guarantee successful
read/write memory operations.

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