libceph: define new ceph_file_layout structure

Define new ceph_file_layout structure and rename old ceph_file_layout
to ceph_file_layout_legacy. This is preparation for adding namespace
to ceph_file_layout structure.

Signed-off-by: Yan, Zheng <zyan@redhat.com>
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 0daaf7c..cba5dcf 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -1583,9 +1583,9 @@
 {
 	int ret = 0;
 	struct ceph_inode_info *ci = ceph_inode(inode);
-	s32 stripe_unit = ceph_file_layout_su(ci->i_layout);
-	s32 stripe_count = ceph_file_layout_stripe_count(ci->i_layout);
-	s32 object_size = ceph_file_layout_object_size(ci->i_layout);
+	s32 stripe_unit = ci->i_layout.stripe_unit;
+	s32 stripe_count = ci->i_layout.stripe_count;
+	s32 object_size = ci->i_layout.object_size;
 	u64 object_set_size = object_size * stripe_count;
 	u64 nearly, t;