net, ipw2x00: remove redundant D0 power state set

Pci_enable_device() will set device power state to D0,
so it's no need to do it again in ipw2100_pci_init_one().

Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>