xen/x86: detect support for extended destination ID

Xen allows the usage of some previously reserved bits in the IO-APIC
RTE and the MSI address fields in order to store high bits for the
target APIC ID. Such feature is already implemented by QEMU/KVM and
HyperV, so in order to enable it just add the handler that checks for
it's presence.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220120152527.7524-3-roger.pau@citrix.com


Signed-off-by: Juergen Gross <jgross@suse.com>