drivers/net: Convert unbounded kzalloc calls to kcalloc

These changes may be slightly safer in some instances.

There are other kzalloc calls with a multiply, but those
calls are typically "small fixed #" * sizeof(some pointer)"
and those are not converted.

Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>