labs: kernel: setup: Fix U-Boot instructions

Since we updated U-Boot, the MAC addresses are no longer taken into
account automatically, the usb_ether gadget driver must be reloaded.

Signed-off-by: Miquel Raynal <[email protected]>

labs/kernel-board-setup/kernel-board-setup.tex

@@ -199,6 +199,18 @@ \section{Network configuration on the target}
 saveenv
 \end{verbatim}
 
+As the network USB gadget was loaded and initialized before we changed
+its configuration, you should either restart the device with:
+\begin{verbatim}
+reset
+\end{verbatim}
+or re-bind the ethernet gadget with the USB device controller:
+\begin{verbatim}
+unbind ethernet 1
+bind /ocp/usb@47400000/usb@47401000 usb_ether
+\end{verbatim}
+in order for the new MAC addresses to be taken into consideration.
+
 \section{Network configuration on the PC host}
 
 To configure your network interface on the workstation side, we need