console: adjust IRQ initialization

console: adjust IRQ initialization

In order for a Xen internal PCI device driver to enable MSI on the
device, we need another hook which the driver can use to create the IRQ
(doing this in the init_preirq hook is too early, since IRQ code hasn't
got initialized at that time yet, and doing it in init_postirq is too
late because at least on x86 smp_intr_init() needs to know the IRQ
number).

On x86 this additionally requires a slight ordering change to IRQ
initialization, to facilitate calling the new hook between basic
initialization and the call path leading to smp_intr_init().

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>