EDAC, amd64: Extend ecc_enabled() to Fam17h

EDAC, amd64: Extend ecc_enabled() to Fam17h

Update the ecc_enabled() function to work on Fam17h. This entails
reading a different set of registers and using the SMN (System
Management Network) rather than PCI devices.

Signed-off-by: Yazen Ghannam <Yazen.Ghannam@amd.com>
Cc: Aravind Gopalakrishnan <aravindksg.lkml@gmail.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: x86-ml <x86@kernel.org>
Link: http://lkml.kernel.org/r/1479423463-8536-9-git-send-email-Yazen.Ghannam@amd.com
[ Fixup ecc_en assignment and get_umc_base(). ]
Signed-off-by: Borislav Petkov <bp@suse.de>