Motherboard in itself does not need any drivers because it's basically something which holds standards components, like CPU, RAM, PCI-E slots, onboard devices, etc. and they all communicate using standards protocols which are initialized on boot and managed by the kernel via the CPU.
And all these components are shared between motherboard manufactures, they are all pretty standard and in most cases have datasheets which allow to "talk" to them, i.e. to work with them via drivers. Some devices are poorly documented or have no datasheets, that's why Linux struggles to support them, e.g. lots of hardware monitoring chips are barely or not supported by Linux.
When you install "motherboard drivers" in Windows, you do not install "motherboard" drivers, you install drivers for individual devices which the motherboard contains.