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

Call them from their respective hw_info_get() paths.

Call the new functions after the setting the chip select base and mask
counts, since those are need to read the correct number of chip select
base and mask registers. And call the new functions before the remaining
set up, because the base and mask register values will be needed later.

  [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/20230127170419.1824692-14-yazen.ghannam@amd.com