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

This reverts commit bbe48176c98220e7ec743ec73736b8ded6a7afd2.



Change-Id: I03d2039dd65671c569c166aa3dfecf6929ceb276
Signed-off-by: doc <doc.divxm@gmail.com>