Revert "n_tty: Fix n_tty_write crash when echoing in raw mode"

I swear I committed this, built it and tested it this morning.  Yet, there is no way this can compile.  It uses a struct that is never defined in the kernel.

Sigh.

This reverts commit 2e3507df08ce07323078874365b34048441edc0d.

Change-Id: I1598ec8fc6cff80d3e030c188502ddaa5d27e614