dt-bindings: display: renesas,du: narrow interrupts and resets per variants

Each variable-length property like interrupts or resets must have fixed
constraints on number of items for given variant in binding.  The
clauses in "if:then:" block should define both limits: upper and lower.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250128094719.63776-1-krzysztof.kozlowski@linaro.org