net: e1000: Add initialized eth_device & e1000_hw structure

nic and hw structures are allocated via malloc i.e. return memory
is not zero initialized. Because of this few structure member like
"function pointers" are initialized with garbage values.

It may cause problem. for eg. during eth_initialize, dev->write_hwaddr
is used.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

Fixed typo.
Signed-off-by: Wolfgang Denk <wd@denx.de>