xen-platform: convert to memory API Since this device bypasses PCI and registers I/O ports directly with the system bus, it needs further attention. Reviewed-by: Richard Henderson <rth@twiddle.net> Reviewed-by: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>