dt-bindings: rng: atmel,at91-trng: update maintainers entry

Update according to new MAINTAINERS entry.

Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Acked-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/d84760e0b81c338e01f7856e1ce3c5b600b08f23.1643553619.git.nicolas.ferre@microchip.com