riscv: dts: spacemit: add LEDs for Milk-V Jupiter board

riscv: dts: spacemit: add LEDs for Milk-V Jupiter board

The Milk-V Jupiter board provides support for two LEDs through the front
panel header. The "Power LED" indicates the system is running, and the
"HDD LED" shows disk activity. Configure the corresponding LED triggers
accordingly.

Caveats:
- The LEDs are driven through a 4.7k series resistor, making them
  quite faint.
- The disk activity trigger requires a storage controller on the M.2 or
  PCIe interface. That said, it matches the purpose and the vendor
  kernel.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Yixun Lan <dlan@kernel.org>
Link: https://lore.kernel.org/r/20260326183745.1370642-2-aurelien@aurel32.net
Signed-off-by: Yixun Lan <dlan@kernel.org>