usb gadget driver initialization issue

[Zixun Li]

> -----Original Message-----
> From: Marek Vasut <marex at denx.de>
> Sent: Saturday, July 20, 2024 22:12
> 
> Can you please send an RFC patch ?
> 
> > I see recently there are many DM related reworking, please forgive me
> > if it's already on the Todo list.
> 
> It is not on the ToDo list, no.
> 
> +CC Mattijs

Hi, this issue only affects usb_ether, as g_dnl will enter event loop right 
after driver register so the host won't see an un responsive device.

I think one solution is revert half of 718f1d41 to move
 usb_gadget_register_driver()/usb_gadget_unregister_driver() 
back to usb_eth_start()/usb_eth_stop().

It doesn't affect the ability of bind/unbind mentioned by the commit's 
description. In fact by reverting it usb_ether will behaves more like 
running 'ums' or 'dfu', since running a ethernet command like 'dhcp'
will do register->event loop->unregister just like 'ums' does.