nfp: change eeprom length to max length enumerators

Extend the size of QSFP EEPROM for types SSF8436 and SFF8636
from 256 to 640 bytes in order to expose all the EEPROM pages by
ethtool.

For SFF-8636 and SFF-8436 specifications, the driver exposes
256 bytes of EEPROM data for ethtool's get_module_eeprom()
callback, resulting in "netlink error: Invalid argument" when
an EEPROM read with an offset larger than 256 bytes is attempted.

Changing the length enumerators to the _MAX_LEN
variants exposes all 640 bytes of the EEPROM allowing upper
pages 1, 2 and 3 to be read.

Fixes: 96d971e3

 ("ethtool: Add fallback to get_module_eeprom from netlink command")
Signed-off-by: Jaco Coetzee <jaco.coetzee@corigine.com>
Reviewed-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>