genirq/irqdomain: Move bus token enum into a seperate header

Split the bus token defines out into a seperate header file to avoid
inclusion of irqdomain.h in msi.h.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20221111122014.237221143@linutronix.de

include/linux/irqdomain_defs.h

@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_IRQDOMAIN_DEFS_H
+#define _LINUX_IRQDOMAIN_DEFS_H
+
+/*
+ * Should several domains have the same device node, but serve
+ * different purposes (for example one domain is for PCI/MSI, and the
+ * other for wired IRQs), they can be distinguished using a
+ * bus-specific token. Most domains are expected to only carry
+ * DOMAIN_BUS_ANY.
+ */
+enum irq_domain_bus_token {
+	DOMAIN_BUS_ANY		= 0,
+	DOMAIN_BUS_WIRED,
+	DOMAIN_BUS_GENERIC_MSI,
+	DOMAIN_BUS_PCI_MSI,
+	DOMAIN_BUS_PLATFORM_MSI,
+	DOMAIN_BUS_NEXUS,
+	DOMAIN_BUS_IPI,
+	DOMAIN_BUS_FSL_MC_MSI,
+	DOMAIN_BUS_TI_SCI_INTA_MSI,
+	DOMAIN_BUS_WAKEUP,
+	DOMAIN_BUS_VMD_MSI,
+};
+
+#endif /* _LINUX_IRQDOMAIN_DEFS_H */