drm: bridge: it66121: Move VID/PID to new it66121_chip_info structure

This will make it easier later to introduce support for new chips in
this driver.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Robert Foss <robert.foss@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221214130122.12911-1-paul@crapouillou.net