redhat/configs: Cleanup CONFIG_ACPI_AGDI

CONFIG_ACPI_AGDI enables the ARM Generic Diagnostic Dump and Reset
Interface, which by it's very name is ARM specific.

Move the ark entry to an aarch64 specific entry, and then combine the
fedora and ark entries to a common entry.

Signed-off-by: Prarit Bhargava prarit@redhat.com