xen: setup pv irq ops vector earlier

xen: setup pv irq ops vector earlier

Setting pv_irq_ops for Xen PV domains should be done as early as
possible in order to support e.g. very early printk() usage.

The same applies to xen_vcpu_info_reset(0), as it is needed for the
pv irq ops.

Move the call of xen_setup_machphys_mapping() after initializing the
pv functions as it contains a WARN_ON(), too.

Remove the no longer necessary conditional in xen_init_irq_ops()
from PVH V1 times to make clear this is a PV only function.

Cc: <[email protected]> # 4.14
Signed-off-by: Juergen Gross <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>