Constant vm_control::USB_CONTROL_MAX_PORTS

pub const USB_CONTROL_MAX_PORTS: usize = 16;

The maximum number of devices that can be listed in one UsbControlCommand.

This value was set to be equal to xhci_regs::MAX_PORTS for convenience, but it is not necessary for correctness. Importing that value directly would be overkill because it would require adding a big dependency for a single const.