drivers/rtc/rtc-proc.c: add module_put on error path in rtc_proc_open()

In file drivers/rtc/rtc-proc.c seq_open() can return -ENOMEM.

 86        if (!try_module_get(THIS_MODULE))
 87                return -ENODEV;
 88
 89        return single_open(file, rtc_proc_show, rtc);

In this case before exiting (line 89) from rtc_proc_open the
module_put(THIS_MODULE) must be called.

Found by Linux Device Drivers Verification Project
Signed-off-by: Alexander Strakh <strakh@ispras.ru>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-proc.c

@@ -81,12 +81,16 @@ static int rtc_proc_show(struct seq_file *seq, void *offset)
 
 static int rtc_proc_open(struct inode *inode, struct file *file)
 {
+	int ret;
 	struct rtc_device *rtc = PDE(inode)->data;
 
 	if (!try_module_get(THIS_MODULE))
 		return -ENODEV;
 
-	return single_open(file, rtc_proc_show, rtc);
+	ret = single_open(file, rtc_proc_show, rtc);
+	if (ret)
+		module_put(THIS_MODULE);
+	return ret;
 }
 
 static int rtc_proc_release(struct inode *inode, struct file *file)