Documentation: usb: gadget_serial: update generic serial setup instruction
Documentation: usb: gadget_serial: update generic serial setup instruction

Using module parameters to specify accepted Vendor ID, Product ID is
considered legacy now. Update the documentation to reflect it.

Signed-off-by: Andrzej Pietrasiewicz <0bcd4dade8bc9135441847460b651a5ef589ec79@samsung.com>
Signed-off-by: Felipe Balbi <94dddeeef08b001e003cce128ddc162a4e2c6cd2@ti.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs