net: ethtool: Return -EOPNOTSUPP if user space tries to read EEPROM with lengh 0
net: ethtool: Return -EOPNOTSUPP if user space tries to read EEPROM with lengh 0

If a driver supports reading EEPROM but no EEPROM is installed in the system,
the driver's get_eeprom_len function returns 0. ethtool will subsequently
try to read that zero-length EEPROM anyway. If the driver does not support
EEPROM access at all, this operation will return -EOPNOTSUPP. If the driver
does support EEPROM access but no EEPROM is installed, the operation will
return -EINVAL. Return -EOPNOTSUPP in both cases for consistency.

Signed-off-by: Guenter Roeck <ba324ca7b1c77fc20bb970d5aff6eea9377918a5@roeck-us.net>
Tested-by: Andrew Lunn <02e0a999c50b1f88df7a8f5a04e1b76b35ea6a88@lunn.ch>
Signed-off-by: David S. Miller <fe08d3c717adf2ae63592e4c9aec6e3e404d8e3e@davemloft.net>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs