dl2k: stop using net_device.{base_addr, irq} and convert to __iomem.

The eeprom registers always use the same PCI bar whereas the general
registers may either use the same mapping as the eeprom registers or
a different one. It is thus possible to simplify parse_eeprom().

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>