sysfs: kill unnecessary NULL pointer check in sysfs_release()

In sysfs_release(), sysfs_buffer pointed to by filp->private_data is
guaranteed to exist.  Kill the unnecessary NULL check.  This also
makes the code more consistent with the counterpart in fs/sysfs/bin.c.
Signed-off-by: NTejun Heo <htejun@gmail.com>
Acked-by: NCornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

fs/sysfs/file.c

@@ -311,11 +311,10 @@ static int sysfs_release(struct inode * inode, struct file * filp)
 {
 	struct sysfs_buffer *buffer = filp->private_data;
 
-	if (buffer) {
-		if (buffer->page)
-			free_page((unsigned long)buffer->page);
-		kfree(buffer);
-	}
+	if (buffer->page)
+		free_page((unsigned long)buffer->page);
+	kfree(buffer);
+
 	return 0;
 }