logfs: constify logfs_block_ops structures

The logfs_block_ops structures are never modified, so declare them as
const.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/logfs/readwrite.c b/fs/logfs/readwrite.c
index 380d86e..20973c9 100644
--- a/fs/logfs/readwrite.c
+++ b/fs/logfs/readwrite.c
@@ -569,13 +569,13 @@
 }
 
 
-static struct logfs_block_ops inode_block_ops = {
+static const struct logfs_block_ops inode_block_ops = {
 	.write_block = inode_write_block,
 	.free_block = inode_free_block,
 	.write_alias = inode_write_alias,
 };
 
-struct logfs_block_ops indirect_block_ops = {
+const struct logfs_block_ops indirect_block_ops = {
 	.write_block = indirect_write_block,
 	.free_block = indirect_free_block,
 	.write_alias = indirect_write_alias,