mpc85xx: enable error reporting for RAM and PCIe

mpc85xx: enable error reporting for RAM and PCIe

All Freescale processors used in this target are capable to detect error
and correction. [1] It can not be used as kernel module. [2] This is
helpful to report hardware errors.

It enables three kernel options:

- EDAC, which is a subsystem
- EDAC_LEGACY_SYSFS, it enables sysfq nodes
- MP85XX, support for Freescale MPC8349, MPC8560, MPC8540, MPC8548, T4240

EDAC is already enabled for following targets:
qoriq, octeon, octeontx and zynq.

[1] https://cateee.net/lkddb/web-lkddb/EDAC.html
[2] https://patchwork.ozlabs.org/patch/554908/

Signed-off-by: Josef Schlehofer <pepe.schlehofer@gmail.com>