EDAC/mce_amd: Add new error descriptions for existing types

A few existing MCA bank types will have new error types in future SMCA
systems.

Add the descriptions for the new error types.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200708153515.1911642-1-Yazen.Ghannam@amd.com