soc/intel/apollolake: clear PMC registers

The clearing of the PMC registers was not being called resulting
in state persisting across reboots. This state is queried and
events are added to the eventlog like 'RTC reset' events. However,
the RTC reset event is a one time thing so it should only be logged
once. Without the clearing of the state the event was logged on
every boot.

BUG=chrome-os-partner:58496

Change-Id: I60aa7102977c2b1775ab8c54d1c147737d2af5e2
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/17027
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Andrey Petrov <andrey.petrov@intel.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

src/soc/intel/apollolake/pmc.c

@@ -152,6 +152,9 @@ static void pmc_init(struct device *dev)
 
 	/* Log power state */
 	pch_log_state();
+
+	/* Now that things have been logged clear out the PMC state. */
+	clear_pmc_status();
 }
 
 static const struct device_operations device_ops = {