[FAQ] AM6442: PCIe clock architecture

with PG2.0 silicon, AM64x can source the PCIE ref clock but it does not support SSC when sourcing the PCIE ref clock.   Validation was performed using common clock topology (ie Root-complex and End-point using the same clock).  So both ends using the same clock as sourced from AM64x PCIE ref clock but NO SSC = OK.  Both ends using same clock as sourced from external source both Yes or No SSC = OK.   Using independent clock sources for Root-complex and End-point = not validated this topology