wil6210: protect against sporadic interrupt during suspend flow

During the suspend flow, wil6210 HW can send sporadic interrupts,
while PCIe bus is not operational.
To prevent that, keep the interrupts disabled during the suspend
flow and re-enable them only after PCIe enablement in resume.

Change-Id: I205f8cdb89c4f64ecac4ca3422767bfc47ec3d33
Signed-off-by: Maya Erez <merez@codeaurora.org>