net/mlx5e: Fix SFF 8472 eeprom length

SFF 8472 eeprom length is 512 bytes. Fix module info return value to
support 512 bytes read.

Fixes: ace329f4

 ("net/mlx5e: ethtool, Remove unsupported SFP EEPROM high pages query")
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Reviewed-by: Aya Levin <ayal@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>