trimming task_work: kill ->data

get rid of the only user of ->data; this is _not_ the final variant - in the
end we'll have task_work and rcu_head identical and just use cred->rcu,
at which point the separate allocation will be gone completely.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 3dcbf86..b510a31 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -148,6 +148,10 @@
 #define KEY_LOOKUP_PARTIAL	0x02
 #define KEY_LOOKUP_FOR_UNLINK	0x04
 
+struct kludge {	/* this will die off very soon */
+	struct task_work twork;
+	struct cred *cred;
+};
 extern long join_session_keyring(const char *name);
 extern void key_change_session_keyring(struct task_work *twork);