Revert "ANDROID: input: misc: keychord: move header to uapi"

This reverts commit f4d1cf12.

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

.

Signed-off-by: Mark Salyzyn <salyzyn@google.com>
Cc: Colin Cross <ccross@android.com>
Bug: 64114943
Bug: 129556081
Change-Id: I788f3cc4bec226fcccdd84127599e291f570087d