wil6210: add support for platform specific notification events

Add the ability to notify the platform driver on different
events, such as FW crash, pre reset and FW ready.

Change-Id: I796b06fae4376cda792d7f26a430ad4580899846
CRs-Fixed: 986135
Signed-off-by: Maya Erez <merez@codeaurora.org>