s390/diag: convert to use DEFINE_SEQ_ATTRIBUTE macro

Use DEFINE_SEQ_ATTRIBUTE macro to simplify the code.
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/kernel/diag.c

@@ -104,18 +104,7 @@ static const struct seq_operations show_diag_stat_sops = {
 	.show	= show_diag_stat,
 };
 
-static int show_diag_stat_open(struct inode *inode, struct file *file)
-{
-	return seq_open(file, &show_diag_stat_sops);
-}
-
-static const struct file_operations show_diag_stat_fops = {
-	.open		= show_diag_stat_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= seq_release,
-};
-
+DEFINE_SEQ_ATTRIBUTE(show_diag_stat);
 
 static int __init show_diag_stat_init(void)
 {