xive: Cleanup calls to set_xive backends
xive: Cleanup calls to set_xive backends

When interrupt sources provide a set_xive backend on P9 that
means they have to do additional work to mask/unmask interrupts
(typically due to issues in their ESB HW implementations).

However, this never involves server targetting. Additionally
there is confusion on what a "server number" means to a set_xive
call due to the pre-P9 encoding, so let's not pass it at all,
pass 0 instead.

Signed-off-by: Benjamin Herrenschmidt <a7089bb6e7e92505d88aaff006cbdd60cc9120b6@kernel.crashing.org>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

shenki/skiboot,stewart-ibm/skiboot,qemu/skiboot,legoater/skiboot,stewart-ibm/skiboot,qemu/skiboot,open-power/skiboot,legoater/skiboot,qemu/skiboot,open-power/skiboot,qemu/skiboot,shenki/skiboot,open-power/skiboot,qemu/skiboot,mikey/skiboot,shenki/skiboot,legoater/skiboot,legoater/skiboot,shenki/skiboot,legoater/skiboot,open-power/skiboot,stewart-ibm/skiboot,mikey/skiboot,open-power/skiboot,mikey/skiboot,shenki/skiboot