ethernet: isa: convert to module_init/module_exit

There are a couple of ISA ethernet drivers that use the old
init_module/cleanup_module function names for the main entry
points, nothing else uses those any more.

Change them to the documented method with module_init()
and module_exit() markers next to static functions.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>