platform/x86: portwell-ec: Add suspend/resume support for watchdog

platform/x86: portwell-ec: Add suspend/resume support for watchdog

Portwell EC does not disable the watchdog during suspend. To avoid unwanted
resets, this patch adds suspend and resume callbacks (pwec_suspend() and
pwec_resume()) to the driver.

The watchdog is stopped in pwec_suspend() and restarted in pwec_resume() if
it was active before suspend.

Signed-off-by: Yen-Chi Huang <jesse.huang@portwell.com.tw>
Link: https://lore.kernel.org/r/c9cfe602-c279-4aa4-9932-76f47f26556c@portwell.com.tw
[ij: removed extra "3"]
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>