Revert "ANDROID: input: keychord: Fix races in keychord_write."

This reverts commit 8253552b.

Remove keychord driver, replaced in user space by
https://android-review.googlesource.com/c/677629

.

Signed-off-by: Mark Salyzyn <salyzyn@google.com>
Bug: 64114943
Bug: 64133562
Bug: 63974334
Bug: 129556081
Change-Id: Ie94621b0adf8b1f8c0d249f74385cc2914b1aec0