USB: show USB 3.2 Dual-lane devices as Gen Xx2 during device enumeration

USB 3.2 specification adds a Gen XxY notion for USB3 devices where X is the signaling rate on the wire. Gen 1xY is 5Gbps Superspeed and Gen 2xY is 10Gbps SuperSpeedPlus. Y is the lane count.

For normal, non inter-chip (SSIC) devies the rx and tx lane count is symmetric, and the maximum lane count for USB 3.2 devices is 2 (dual-lane).

SSIC devices may have asymmetric lane counts, with up to four lanes per direction. The USB 3.2 specification doesn't point out how to use the Gen XxY notion for these devices, so we limit the Gen Xx2 notion to symmertic Dual lane devies.
For other devices just show Gen1 or Gen2