netdev-afxdp: Updated documentation.
If system is missing ethtool, test fails silently.
@@ -167,6 +167,7 @@ Finally, build and install OVS::
To kick start end-to-end autotesting::
uname -a # make sure having 5.0+ kernel
+ ethtool --version # make sure ethtool is installed
make check-afxdp TESTSUITEFLAGS='1'
.. note::
