dt-bindings: rng: atmel,at91-trng: add sama7d65 TRNG

Add compatible for Microchip SAMA7D65 SoC TRNG.

Signed-off-by: Ryan Wanner <Ryan.Wanner@microchip.com>
Reviewed-by: Claudiu Beznea <claudiu.beznea@tuxon.dev>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>