PM / sleep: Fix entering suspend-to-IDLE if no freeze_oops is set

If no freeze_ops is set, trying to enter suspend-to-IDLE will cause a
nice oops in platform_suspend_prepare_late(). Add respective checks to
platform_suspend_prepare_late() and platform_resume_early() functions.

Fixes: a8d46b9e4e48 (ACPI / sleep: Rework the handling of ACPI GPE wakeup ...)
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

kernel/power/suspend.c

@@ -146,7 +146,7 @@ static int platform_suspend_prepare(suspend_state_t state)
 
 static int platform_suspend_prepare_late(suspend_state_t state)
 {
-	return state == PM_SUSPEND_FREEZE && freeze_ops->prepare ?
+	return state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->prepare ?
 		freeze_ops->prepare() : 0;
 }
 
@@ -164,7 +164,7 @@ static void platform_resume_noirq(suspend_state_t state)
 
 static void platform_resume_early(suspend_state_t state)
 {
-	if (state == PM_SUSPEND_FREEZE && freeze_ops->restore)
+	if (state == PM_SUSPEND_FREEZE && freeze_ops && freeze_ops->restore)
 		freeze_ops->restore();
 }