xen: Remove support for PV ACPI cpu/memory hotplug

xen: Remove support for PV ACPI cpu/memory hotplug

Commit b616a49ede70 ("xen/acpi-stub: Disable it b/c the acpi_processor_add
is no longer called.") declared as BROKEN support for Xen ACPI stub (which
is required for xen-acpi-{cpu|memory}-hotplug) and suggested that this
is temporary and will be soon fixed. This was in March 2013.

Further, commit 6b5a86233233 ("xen: rename dom0_op to platform_op")
renamed an interface used by memory hotplug code without updating that
code (as it was BROKEN and therefore not compiled). This was
in November 2015 and has gone unnoticed for over 5 year.

It is now clear that this code is of no interest to anyone and therefore
should be removed.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/1618336344-3162-1-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Juergen Gross <jgross@suse.com>