irqchip/gicv3-its: Sets IRQ_DOMAIN_FLAG_MSI_REMAP

The GICv3 ITS is MSI remapping capable. Let's advertise
this property so that VFIO passthrough can assess IRQ safety.
Signed-off-by: NEric Auger <eric.auger@redhat.com>
Reviewed-by: NMarc Zyngier <marc.zyngier@arm.com>
Reviewed-by: NTomasz Nowicki <tomasz.nowicki@caviumnetworks.com>
Tested-by: NTomasz Nowicki <tomasz.nowicki@caviumnetworks.com>
Tested-by: NBharat Bhushan <bharat.bhushan@nxp.com>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

drivers/irqchip/irq-gic-v3-its.c

@@ -1642,6 +1642,7 @@ static int its_init_domain(struct fwnode_handle *handle, struct its_node *its)
 
 	inner_domain->parent = its_parent;
 	inner_domain->bus_token = DOMAIN_BUS_NEXUS;
+	inner_domain->flags |= IRQ_DOMAIN_FLAG_MSI_REMAP;
 	info->ops = &its_msi_domain_ops;
 	info->data = its;
 	inner_domain->host_data = info;