The ili9882t touch screen chip same as Elan eKTH6915 controller
has a reset gpio. The difference is that ili9882t needs to use
vccio-supply instead of vcc33-supply. Doug's series[1] allows panels
and touchscreens to power on/off together, let's add a phandle for this.

[1]: https://lore.kernel.org/r/20230607215224.2067679-1-dianders@chromium.orgReviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Cong Yang <yangcong5@huaqin.corp-partner.google.com>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20230802071947.1683318-2-yangcong5@huaqin.corp-partner.google.comSigned-off-by: Benjamin Tissoires <bentiss@kernel.org>