How to change Width x8 (lanes) to Width x16 (lanes) for Mellanox ConnectX-4

Hello,

We have installed Mellanox ConnectX-4 Network adapters.
As per the specs, width should be x16. However we see that the width is only x8.

Can you please suggest if there is any command to change this settings to X16(16 lanes)

LnkCap: Port #0, Speed 8GT/s, Width x16, ASPM not supported
LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk+
LnkSta: Speed 8GT/s, Width x8, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete-, EqualizationPhase1-

What is the card OPN?