The function gem_begin_auto_negotiation dereference
the pointer ep before testing if it's null. This
patch add a check on ep before dereferencing it.
This issue was added by the patch 92552fdd557:
"net: sun: sungem: use new api ethtool_{get|set}_link_ksettings".
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>[...]
Signed-off-by: Philippe Reynes <tremyfr@xxxxxxxxx>