ne2k-pci: Add pci_disable_device in error handling

For linux-3.18.0
The driver lacks pci_disable_device in error handling code of
ne2k_pci_init_one, so the device enabled by pci_enable_device is not
disabled when errors occur.
This patch fixes this problem.

Signed-off-by: Jia-Ju Bai <baijiaju1990@163.com>
Signed-off-by: David S. Miller <davem@davemloft.net>