wlcore/wl18xx : add time sync event handling

Added support for a new time sync event
the event data contains the WiLink TSF value.
To trigger the event, a HW modification is required,
so as a supporting firmware binary.

Signed-off-by: Yaniv Machani <yanivma@ti.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>