When injecting DRAM ECC errors (F3xBC_x8), EccVector[15:0] is a bitmask
of which bits should be error injected when written to and holds the
payload of 16-bit DRAM word when read, respectively.

Add /sysfs members to show the DRAM ECC section/word/vector.

Fail wrong injection values entered over /sysfs instead of truncating
them.
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>

Borislav:
- rename sysfs attrs to more conform names
- cleanup/fix comments according to BKDG text
- fix function return value patterns
- cleanup debug calls
Reviewed-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: NDoug Thompson <dougthompson@xmission.com>
Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>