EDAC/amd64: Split ecc_enabled() into dct/umc functions

Call them using a function pointer in pvt->ops. The "ECC enabled"
check is done outside of the hardware information gathering done in
hw_info_get(). So a high-level function pointer is needed to separate
the legacy and modern paths.

No functional change is intended.

  [Yazen: rebased/reworked patch and reworded commit message. ]

Signed-off-by: Muralidhara M K <muralidhara.mk@amd.com>
Co-developed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@amd.com>
Signed-off-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@amd.com>
Co-developed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20230127170419.1824692-17-yazen.ghannam@amd.com