Track base pointer to d20557f7 (xHCI 1.1+ feature gating: LEC/U3C/CIC
gates, HW LPM substrate with protocol-caps HLC detection, PORTPMSC
register-target fix, bogus HCCPARAMS1-HLC accessor removed).
Mark P2-B COMPLETE in USB-IMPLEMENTATION-PLAN.md with the full gating
inventory and Linux 7.1 cross-references. Per-device L1 enablement
(BESL, MEL Evaluate Context) explicitly deferred to P3 hub work.
vasilito
d3e5fc0a82