doc: interrupts: fix Direct ISR code example

- Fixes Direct ISR code example.
- Deletes the wrong comment,
  which was likely copy-pasted from
  the previous ISR code example.

Signed-off-by: Andrej Butok <[email protected]>

Author: butok

doc/kernel/services/interrupts.rst

@@ -336,7 +336,6 @@ The following code demonstrates a direct ISR:
 
     #define MY_DEV_IRQ  24       /* device uses IRQ 24 */
     #define MY_DEV_PRIO  2       /* device uses interrupt priority 2 */
-    /* argument passed to my_isr(), in this case a pointer to the device */
     #define MY_IRQ_FLAGS 0       /* IRQ flags */
 
     ISR_DIRECT_DECLARE(my_isr)