dt-bindings: update Luca Ceresoli's e-mail address

My Bootlin address is preferred from now on.

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220603155727.1232061-2-luca@lucaceresoli.net