net/mlx5e: Fix wrong return value on ioctl EEPROM query failure

The ioctl EEPROM query wrongly returns success on read failures, fix
that by returning the appropriate error code.

Fixes: bb64143e

 ("net/mlx5e: Add ethtool support for dump module EEPROM")
Signed-off-by: Gal Pressman <gal@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>