Add Supermicro memory MRC and memory RAS

[AlexanderAmelkin]

Reported by: K.C. Li
Original Ticket: ipmitool/bugs/496

1. Add the SEL parsing for memory MRC on supermicro systems.
2. Add the SEL parsing for memory RAS on supermicro systems.
3. Add chipset type 6 for supermicro memory ecc.
4. Add more support systems for supermicro memory ecc.

[AlexanderAmelkin]

Modify the MRC to distinguish Purley and Grantley.

Original comment by: K.C. Li