amd64_edac: Modify usage of amd64_read_dct_pci_cfg()

Rationale behind this change:
 - F2x1xx addresses were stopped from being mapped explicitly to DCT1
   from F15h (OR) onwards. They use _dct[0:1] mechanism to access the
   registers. So we should move away from using address ranges to select
   DCT for these families.
 - On newer processors, the address ranges used to indicate DCT1 (0x140,
   0x1a0) have different meanings than what is assumed currently.

Changes introduced:
 - amd64_read_dct_pci_cfg() now takes in dct value and uses it for
   'selecting the dct'
 - Update usage of the function. Keep in mind that different families
   have specific handling requirements
 - Remove [k8|f10]_read_dct_pci_cfg() as they don't do much different
   from amd64_read_pci_cfg()
   - Move the k8 specific check to amd64_read_pci_cfg
 - Remove f15_read_dct_pci_cfg() and move logic to amd64_read_dct_pci_cfg()
 - Remove now needless .read_dct_pci_cfg

Testing:
 - Tested on Fam 10h; Fam15h Models: 00h, 30h; Fam16h using 'EDAC_DEBUG'
   and mce_amd_inj
 - driver obtains info from F2x registers and caches it in pvt
   structures correctly
 - ECC decoding works fine

Signed-off-by: Aravind Gopalakrishnan <aravind.gopalakrishnan@amd.com>
Link: http://lkml.kernel.org/r/1410799058-3149-1-git-send-email-aravind.gopalakrishnan@amd.com
Signed-off-by: Borislav Petkov <bp@suse.de>