[S390] Fix sparse warnings.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/hypfs/hypfs_diag.c b/arch/s390/hypfs/hypfs_diag.c
index efa74af..1785bce 100644
--- a/arch/s390/hypfs/hypfs_diag.c
+++ b/arch/s390/hypfs/hypfs_diag.c
@@ -403,7 +403,7 @@
 		*pages = 1;
 		return diag204_alloc_rbuf();
 	} else {/* INFO_EXT */
-		*pages = diag204(SUBC_RSI | INFO_EXT, 0, 0);
+		*pages = diag204(SUBC_RSI | INFO_EXT, 0, NULL);
 		if (*pages <= 0)
 			return ERR_PTR(-ENOSYS);
 		else