UBUNTU: [Config] set EDAC_MM_EDAC=y for ARM64

UBUNTU: [Config] set EDAC_MM_EDAC=y for ARM64

Setting EDAC_MM_EDAC=y automatically enables EDAC_GHES on ARM64. ARMv8.0
systems lack standard RAS architecture (or machine check architecture
equivalent).

EDAC_GHES is essential for ARMv8.0 Servers, it enables firmware-first
error handling of memory and CPU errors. APEI/GHES is the only mechanism
available for reporting hardware errors (e.g. memory and CPU errors),
and helps enable memory fault recovery mechanisms to extend the life of
the system by offlining pages when recoverable uncorrected errors are
encountered.

BugLink: https://launchpad.net/bugs/1706141
Signed-off-by: Manoj Iyer <manoj.iyer@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>