genirq: Fix comment describing suspend_device_irqs()

The kerneldoc comment describing suspend_device_irqs() is currently
misleading, because generally the function doesn't really disable
interrupt lines at the chip level.  Replace it with a more accurate
one.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
LKML-Reference: <200907050022.35117.rjw@sisk.pl>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/irq/pm.c

@@ -15,10 +15,10 @@
 /**
  * suspend_device_irqs - disable all currently enabled interrupt lines
  *
- * During system-wide suspend or hibernation device interrupts need to be
- * disabled at the chip level and this function is provided for this purpose.
- * It disables all interrupt lines that are enabled at the moment and sets the
- * IRQ_SUSPENDED flag for them.
+ * During system-wide suspend or hibernation device drivers need to be prevented
+ * from receiving interrupts and this function is provided for this purpose.
+ * It marks all interrupt lines in use, except for the timer ones, as disabled
+ * and sets the IRQ_SUSPENDED flag for each of them.
  */
 void suspend_device_irqs(void)
 {