wil6210: add support for PCIe D3hot in system suspend

In order to preserve the connection in suspend/resume flow,
wil6210 host allows going to PCIe D3hot state in suspend,
instead of performing a full wil6210 device reset. This
requires the platform ability to initiate wakeup in case of
RX data. To check that, a new platform API is added.
In addition, add cfg80211 suspend/resume callbacks
implementation.

Change-Id: I3846eaaa8d6e9ecbe5adbb0c04c7574865d5af5e
Signed-off-by: Maya Erez <merez@codeaurora.org>