Adding platform support for centec v682-48y8c_d.
Why I did it
Adding platform support for centec v682-48y8c_d.
This switch has 48 SFP+ (1G/10G/25G) ports, 8 QSFP28 (40G/100G) ports on CENTEC TsingMa.MX.
CPU used in v682-48y8c_d is Intel(R) Xeon(R) CPU D-1527.
How I did it
Modify related code in platform and device directory.
Upgrade sai to v1.8.
fix bug for parallel compile centec platform modules.
How to verify it
Build centec amd64 sonic image, verify platform functions (port, sfp, led etc) on centec v682-48y8c_d board.
Co-authored-by: Shi Lei <shil@centecnetworks.com>
