vfs: Use const for kernel parser table

This is a much better version of a previous patch to make the parser
tables constant. Rather than changing the typedef, we put the "const" in
all the various places where its required, allowing the __initconst
exception for nfsroot which was the cause of the previous trouble.

This was posted for review some time ago and I believe its been in -mm
since then.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Alexander Viro <aviro@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 448dfd5..8ebe9a5 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -211,7 +211,7 @@
        ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
        ecryptfs_opt_encrypted_view, ecryptfs_opt_err };
 
-static match_table_t tokens = {
+static const match_table_t tokens = {
 	{ecryptfs_opt_sig, "sig=%s"},
 	{ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
 	{ecryptfs_opt_cipher, "cipher=%s"},