[SRU Zesty][Artful] Enable EDAC_GHES support in ARM64

[Manoj Iyer]

Please review and consider this SRU to Zesty and apply to Artful. 
This patch to Ubuntu config adds EDAC_GHES support to ARM64 systems.
Tracked in bug: https://launchpad.net/bugs/1706141

Pre-requisite: The RAS patch series that was submitted previously
as SRU to Zesty is a pre-requisite to this patch. This patch was
fix-committed to Artful and is pending SRU to zesty. This is tracked in
bug: https://launchpad.net/bugs/1696570

Also please note that you will need to remove edac_core from
debian.master/abi/<ver>/arm64/generic.modules when you bump ABI after
applying this patch.

This patch was regression tested on AMD64, Power8 and 4 different
ARM64 systems. Details of tests and test kernel can be found in the bug:
https://launchpad.net/bugs/1706141. The test kernel based on Ubuntu Zesty
tag Ubuntu-4.10.0-29.33 with RAS patches and this config patch applied
was tested by me as well as Qualcomm for functionality, and test results
were posted to the bug report as comments by me and Tyler Baicar.

Also, we have been testing the early incarnation of the RAS patches along
with the GHES support for quite sometime in the periodic Xenial UOSE builds 
we did for QDF2400 systems. We therefore have high degree of confidence 
that the RAS patches and the EDAC_GHES support works as expected on 
QDF2400 systems, and poses a low degree of regression risk on other
architectures.