Provides touchpad_update_write functions that fw_update.c uses
to update the FW over the USB updater interface.
BRANCH=none
BUG=b:63993173, b:65188846
TEST=./usb_updater2 -t touchpad.bin
CQ-DEPEND=CL:593373
Change-Id: I5246cbfa65311cd6f0b1872f9bbc164f3a972153
Signed-off-by: Chun-Ta Lin <itspeter@google.com>
Reviewed-on: https://chromium-review.googlesource.com/601814
Commit-Ready: Chun-ta Lin <itspeter@chromium.org>
Tested-by: Chun-ta Lin <itspeter@chromium.org>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>