MAINTAINERS: fix path to ilitek, ili9225 device tree bindings

This fixes the path to the ilitek,ili9225 device tree binding file.

Signed-off-by: David Lechner <david@lechnology.com>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180525193623.15533-2-david@lechnology.com