Revert "zram: convert remaining CLASS_ATTR() to CLASS_ATTR_RO()"

Turns out that the permissions for 0400 really are what we want here,
otherwise any user can read from this file.

[fixed formatting, added changelog, and made attribute static - gregkh]
Reported-by: Wade Mealing <wmealing@redhat.com>
Cc: stable <stable@vger.kernel.org>
Fixes: f40609d1 ("zram: convert remaining CLASS_ATTR() to CLASS_ATTR_RO()")
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1847832Reviewed-by: Steffen Maier <maier@linux.ibm.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Link: https://lore.kernel.org/r/20200617114946.GA2131650@kroah.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/block/zram/zram_drv.c

@@ -2021,7 +2021,8 @@ static ssize_t hot_add_show(struct class *class,
 		return ret;
 	return scnprintf(buf, PAGE_SIZE, "%d\n", ret);
 }
-static CLASS_ATTR_RO(hot_add);
+static struct class_attribute class_attr_hot_add =
+	__ATTR(hot_add, 0400, hot_add_show, NULL);
 
 static ssize_t hot_remove_store(struct class *class,
 			struct class_attribute *attr,