Revert "usb: gadget: u_ether: Replace netif_stop_queue with netif_device_detach"

This reverts commit f49449fb

.

This commit breaks u_ether on some setups (at least Merrifield). The fix
"usb: gadget: u_ether: Re-attach netif device to mirror detachment" party
restores u-ether. However the netif usb: remains up even usb is switched
from device to host mode. This creates problems for user space as the
interface remains in the routing table while not realy present and network
managers (connman) not detecting a network change.

Various attempts to find the root cause were unsuccesful up to now. Therefore
revert until a solution is found.

Link: https://lore.kernel.org/linux-usb/20231006141231.7220-1-hgajjar@de.adit-jv.com/
Reported-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Reported-by: Ferry Toth <fntoth@gmail.com>
Fixes: f49449fb

 ("usb: gadget: u_ether: Replace netif_stop_queue with netif_device_detach")
Cc: stable@vger.kernel.org
Signed-off-by: Ferry Toth <fntoth@gmail.com>
Link: https://lore.kernel.org/r/20240620204832.24518-3-ftoth@exalondelft.nl
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>