[AVR32] Remove bogus comment in arch/avr32/kernel/irq.c

The comment at the top of arch/avr32/kernel/irq.c doesn't really make
sense anymore since most of the actual interrupt handling code is
elsewhere.

Signed-off-by: Haavard Skinnemoen <[e-mail]>

arch/avr32/kernel/irq.c

···
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
- *
- * This file contains the code used by various IRQ handling routines:
- * asking for different IRQ's should be done through these routines
- * instead of just grabbing them. Thus setups with different IRQ numbers
- * shouldn't result in any weird surprises, and installing new handlers
- * should be easier.
- *
- * IRQ's are in fact implemented a bit like signal handlers for the kernel.
- * Naturally it's not a 1:1 relation, but there are similarities.
  */
 
 #include <linux/interrupt.h>