arch: arc: _rirq_exit: Comment clean-up

We manage IRQs in a quite a different way now since
commit f8d061f ("arch: arc: add nested interrupt support")
so that comment not only makes no sense but also may fool a reader
as disabling of interrupts happens in the very beginning of
_rirq_exit() but not here.

Signed-off-by: Alexey Brodkin <[email protected]>

Author: abrodkin

arch/arc/core/regular_irq.S

@@ -115,11 +115,6 @@ SECTION_FUNC(TEXT, _rirq_exit)
 	mov r1, _kernel
 	ld_s r2, [r1, _kernel_offset_to_current]
 
-	/*
-	 * Lock interrupts to ensure kernel queues do not change from this
-	 * point on until return from interrupt.
-	 */
-
 	/*
 	 * Both (a)reschedule and (b)non-reschedule cases need to load the
 	 * current thread's stack, but don't have to use it until the decision