arm64: debug: Remove meaningless comment

The comment next to the definition of our 'break_hook' list head is
at best wrong but mainly just meaningless. Rip it out.
Reviewed-by: NMark Rutland <mark.rutland@arm.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

arch/arm64/kernel/debug-monitors.c

@@ -264,11 +264,6 @@ static int single_step_handler(unsigned long unused, unsigned int esr,
 }
 NOKPROBE_SYMBOL(single_step_handler);
 
-/*
- * Breakpoint handler is re-entrant as another breakpoint can
- * hit within breakpoint handler, especically in kprobes.
- * Use reader/writer locks instead of plain spinlock.
- */
 static LIST_HEAD(break_hook);
 static DEFINE_SPINLOCK(break_hook_lock);