cpu.h: fix a typo in comment

Found by reading the code.
Signed-off-by: NLi Qiang <liq3ea@gmail.com>
Message-Id: <1536150548-2797-1-git-send-email-liq3ea@gmail.com>
Signed-off-by: NLaurent Vivier <laurent@vivier.eu>

include/qom/cpu.h

@@ -852,7 +852,7 @@ extern CPUInterruptHandler cpu_interrupt_handler;
 /**
  * cpu_interrupt:
  * @cpu: The CPU to set an interrupt on.
- * @mask: The interupts to set.
+ * @mask: The interrupts to set.
  *
  * Invokes the interrupt handler.
  */