hw/arm/npcm8xx_boards: Correct valid_cpu_types setting of NPCM8XX SoC

hw/arm/npcm8xx_boards: Correct valid_cpu_types setting of NPCM8XX SoC

NPCM8XX SoC is the successor of the NPCM7XX. It features quad-core
Cortex-A35 (Armv8, 64-bit) CPUs and some additional peripherals.
Correct the `valid_cpu_types` setting to match the NPCM8XX SoC.

Cc: qemu-stable@nongnu.org
Fixes: 7e70eb3cad7c83 ("hw/arm: Add NPCM845 Evaluation board")
Signed-off-by: Tim Lee <timlee660101@gmail.com>
Message-id: 20250428022934.3081139-1-timlee660101@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Tyrone Ting <kfting@nuvoton.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>