dt-bindings: cros-ec: Add ChromeOS fingerprint binding

Add a binding to describe the fingerprint processor found on Chromebooks
with a fingerprint sensor. Previously we've been describing this with
the google,cros-ec-spi binding but it lacks gpio and regulator control
used during firmware flashing.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
Cc: <devicetree@vger.kernel.org>
Cc: <chrome-platform@lists.linux.dev>
Cc: Guenter Roeck <groeck@chromium.org>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Craig Hesling <hesling@chromium.org>
Cc: Tom Hughes <tomhughes@chromium.org>
Cc: Alexandru M Stan <amstan@chromium.org>
Cc: Tzung-Bi Shih <tzungbi@kernel.org>
Cc: Matthias Kaehlcke <mka@chromium.org>
Cc: Benson Leung <bleung@chromium.org>
Cc: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20221026003641.2688765-3-swboyd@chromium.org