EDAC/amd64: Remove PCI Function 6

PCI Function 6 is used on Family 17h and later to access scrub
registers. With scrub access removed, this function has no other use.

Remove all Function 6 PCI IDs and related code.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230127170419.1824692-4-yazen.ghannam@amd.com