mm, arc: remove obsolete pagefault oom killer comment

Commit 609838cfed ("mm: invoke oom-killer from remaining unconverted page
fault handlers") converted arc to call pagefault_out_of_memory(), so remove
the comment about future conversion.

Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

arch/arc/mm/fault.c

@@ -159,7 +159,6 @@ good_area:
 		return;
 	}
 
-	/* TBD: switch to pagefault_out_of_memory() */
 	if (fault & VM_FAULT_OOM)
 		goto out_of_memory;
 	else if (fault & VM_FAULT_SIGBUS)