dt-bindings: trivial-devices: Add hitron,hac300s

dt-bindings: trivial-devices: Add hitron,hac300s

Add HiTRON HAC300S PSU to trivial devices since it is simple PMBUS
capable device.

Since this is the first supported device from this vendor, document its
name to the vendor-prefixes.yaml file as well.

Signed-off-by: Vasileios Amoiridis <vasileios.amoiridis@cern.ch>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260119190806.35276-2-vassilisamir@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>