ARM: OMAP2+: wakeupgen: Add comment for unhandled FROZEN transitions

FROZEN hotplug notifiers are not handled and do not have to be. Insert
a comment to remember that the lack of the FROZEN transitions is no
accident.

Cc: Tony Lindgren <tony@atomide.com>
Cc: Santosh Shilimkar <ssantosh@kernel.org>
Cc: linux-omap@vger.kernel.org
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/omap-wakeupgen.c

@@ -320,6 +320,11 @@ static int irq_cpu_hotplug_notify(struct notifier_block *self,
 {
 	unsigned int cpu = (unsigned int)hcpu;
 
+	/*
+	 * Corresponding FROZEN transitions do not have to be handled,
+	 * they are handled by at a higher level
+	 * (drivers/cpuidle/coupled.c).
+	 */
 	switch (action) {
 	case CPU_ONLINE:
 		wakeupgen_irqmask_all(cpu, 0);