[netdrvr] epic100: minor cleanups

- Remove in-source changelog, it's in the global kernel history.
- convert silly and useless version to useful one
- replace invariant pci_id_tbl[]::io_size uses with EPIC_TOTAL_SIZE
- remove now-unused io_size member from pci_id_tbl[]
- current kernel style prefers dev_printk() for the rare ethernet driver
  messages that cannot print an 'eth%d' prefix.

Signed-off-by: Jeff Garzik <jeff@garzik.org>