NFS: Fix a number of sparse warnings

Fix a number of "warning: symbol 'foo' was not declared. Should it be
static?" conditions.

Fix 2 cases of "warning: Using plain integer as NULL pointer"

fs/nfs/delegation.c:263:31: warning: restricted fmode_t degrades to integer
  - We want to allow upgrades to a WRITE delegation, but should otherwise
    consider servers that hand out duplicate delegations to be borken.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c
index 12de883..89af1d2 100644
--- a/fs/nfs/delegation.c
+++ b/fs/nfs/delegation.c
@@ -256,11 +256,14 @@
 		/*
 		 * Deal with broken servers that hand out two
 		 * delegations for the same file.
+		 * Allow for upgrades to a WRITE delegation, but
+		 * nothing else.
 		 */
 		dfprintk(FILE, "%s: server %s handed out "
 				"a duplicate delegation!\n",
 				__func__, clp->cl_hostname);
-		if (delegation->type <= old_delegation->type) {
+		if (delegation->type == old_delegation->type ||
+		    !(delegation->type & FMODE_WRITE)) {
 			freeme = delegation;
 			delegation = NULL;
 			goto out;