edac: move documentation from edac_pci*.c to edac_pci.h

Several functions are documented at edac_pci.c and edac_pci_sysfs.c.

As we'll be including edac_pci.h at drivers-api book, move those,
in order for the kernel-doc markups be part of the API
documentation book.

As several of those kernel-doc macros are not in the right format,
fix them.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

edac: move EDAC PCI definitions to drivers/edac/edac_pci.h

The edac_core.h header contain data structures and function
definitions for the 3 parts of EDAC: MC, PCI and device.

Let's move the PCI ones to a separate header file, as part
of a header reorganization.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>