cxgb4: Remove unused vpd_param member ec

Member ec isn't used, so remove it.

Link: https://lore.kernel.org/r/30648e95-bfb9-9af3-0c8f-dd3e34df8b6b@gmail.com


Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>