Adding platform support for FS s5800-48t4s and s5800-48t8s-mars8p.
Both s5800-48t4s and s5800-48t8s-mars8p have 48 * 10/100/1000 Base-T ports, 4 * 10GE SFP+ Ports on Centec TsingMa.
s5800-48t4s is different from s5800-48t8s-mars8p in that:
The phy chip used by s5800-48t4s is Marvell 88e1680;
The phy chip used by s5800-48t4s-mars8p is Centec ctc21108;
