x86, mce: add comment about mce_chrdev_ops being writable

Add a comment explaining that mce_chrdev_ops is intentionally
writable.

[ Impact: comment only ]
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

arch/x86/kernel/cpu/mcheck/mce.c

@@ -940,6 +940,7 @@ static long mce_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 	}
 }
 
+/* Modified in mce-inject.c, so not static or const */
 struct file_operations mce_chrdev_ops = {
 	.open			= mce_open,
 	.release		= mce_release,