KVM: Use irq routing API for MSI

Merge MSI userspace interface with IRQ routing table. Notice the API have been
changed, and using IRQ routing table would be the only interface kvm-userspace
supported.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c03a0a9..339eda3 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -116,6 +116,7 @@
 			unsigned irqchip;
 			unsigned pin;
 		} irqchip;
+		struct msi_msg msi;
 	};
 	struct list_head link;
 };
@@ -327,7 +328,6 @@
 	int host_irq;
 	bool host_irq_disabled;
 	int guest_irq;
-	struct msi_msg guest_msi;
 #define KVM_ASSIGNED_DEV_GUEST_INTX	(1 << 0)
 #define KVM_ASSIGNED_DEV_GUEST_MSI	(1 << 1)
 #define KVM_ASSIGNED_DEV_HOST_INTX	(1 << 8)