This patch changes tcp_ctloutput_[gs]et() such they expect the inp to be write locked. This is a preparation to allow to call tcp_ctloutput_set() from contexts other than setsockopt(). Support for this will come in a follow-up commit.
While there, change the function signatures to pass only the inp around and have this as the first parameter as suggested by glebius@ to simplify future work.
No functional change intended with this change.