Heiko does not work at Theobroma Systems anymore and the boards using
those panels are downstream, maintained internally by the company, so
let's relieve Heiko of maintainership duties.

Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Quentin Schulz <foss+kernel@0leil.net>
Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220131165439.717713-1-quentin.schulz@theobroma-systems.com