rtc/proc: switch to proc_create_single_data

And stop trying to get a reference on the submodule, procfs code deals
with release after an unloaded module and thus removed proc entry.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-proc.c

@@ -107,40 +107,11 @@ static int rtc_proc_show(struct seq_file *seq, void *offset)
 	return 0;
 }
 
-static int rtc_proc_open(struct inode *inode, struct file *file)
-{
-	int ret;
-	struct rtc_device *rtc = PDE_DATA(inode);
-
-	if (!try_module_get(rtc->owner))
-		return -ENODEV;
-
-	ret = single_open(file, rtc_proc_show, rtc);
-	if (ret)
-		module_put(rtc->owner);
-	return ret;
-}
-
-static int rtc_proc_release(struct inode *inode, struct file *file)
-{
-	int res = single_release(inode, file);
-	struct rtc_device *rtc = PDE_DATA(inode);
-
-	module_put(rtc->owner);
-	return res;
-}
-
-static const struct file_operations rtc_proc_fops = {
-	.open		= rtc_proc_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= rtc_proc_release,
-};
-
 void rtc_proc_add_device(struct rtc_device *rtc)
 {
 	if (is_rtc_hctosys(rtc))
-		proc_create_data("driver/rtc", 0, NULL, &rtc_proc_fops, rtc);
+		proc_create_single_data("driver/rtc", 0, NULL, rtc_proc_show,
+				rtc);
 }
 
 void rtc_proc_del_device(struct rtc_device *rtc)