Differences between MIPI-CSI1 and MIPI-CSI2
The lanes are defined at the physical layer (PHY), and are not limited in CSI-2:

"CSI-2 over C/D-PHY imaging interface does not limit the number of lanes per link. Transmission rate linearly scales with the number of lanes for both C-PHY and D-PHY."

No only that but CSI-2 defines more than one PHY:

"C-PHY 1.0, D-PHY v1.2  or “combo C/D-PHY” possible"

All of that is irrelevant at the protocol level.  The lanes simply increase bandwidth.