PM: Reintroduce dropped call to check_wakeup_irqs

Patch 2e711c04
(PM: Remove sysdev suspend, resume and shutdown operations)
deleted sysdev_suspend(), which was being relied on to call
check_wakeup_irqs() in suspend.  If check_wakeup_irqs() is not
called, wake interrupts that are pending when suspend is
entered may be lost.  It also breaks IRQCHIP_MASK_ON_SUSPEND,
which is handled in check_wakeup_irqs().

This patch adds a call to check_wakeup_irqs() in syscore_suspend(),
similar to what was deleted in sysdev_suspend().
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

drivers/base/syscore.c

@@ -9,6 +9,7 @@
 #include <linux/syscore_ops.h>
 #include <linux/mutex.h>
 #include <linux/module.h>
+#include <linux/interrupt.h>
 
 static LIST_HEAD(syscore_ops_list);
 static DEFINE_MUTEX(syscore_ops_lock);
@@ -48,6 +49,13 @@ int syscore_suspend(void)
 	struct syscore_ops *ops;
 	int ret = 0;
 
+	pr_debug("Checking wakeup interrupts\n");
+
+	/* Return error code if there are any wakeup interrupts pending. */
+	ret = check_wakeup_irqs();
+	if (ret)
+		return ret;
+
 	WARN_ONCE(!irqs_disabled(),
 		"Interrupts enabled before system core suspend.\n");