PCI/MSI: Move code into a separate directory

msi.c is getting larger and really could do with a splitup. Move it into
its own directory to prepare for that.

Signed-off-by: Thomas Gleixner <[e-mail]>
Tested-by: Juergen Gross <[e-mail]>
Reviewed-by: Jason Gunthorpe <[e-mail]>
Acked-by: Bjorn Helgaas <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

Documentation/driver-api/pci/pci.rst

···
 .. kernel-doc:: drivers/pci/search.c
    :export:
 
-.. kernel-doc:: drivers/pci/msi.c
+.. kernel-doc:: drivers/pci/msi/msi.c
    :export:
 
 .. kernel-doc:: drivers/pci/bus.c

drivers/pci/Makefile

···
 obj-$(CONFIG_PCI)		+= access.o bus.o probe.o host-bridge.o \
 				   remove.o pci.o pci-driver.o search.o \
 				   pci-sysfs.o rom.o setup-res.o irq.o vpd.o \
-				   setup-bus.o vc.o mmap.o setup-irq.o msi.o
+				   setup-bus.o vc.o mmap.o setup-irq.o
 
+obj-$(CONFIG_PCI)		+= msi/
 obj-$(CONFIG_PCI)		+= pcie/
 
 ifdef CONFIG_PCI

drivers/pci/msi.c drivers/pci/msi/msi.c

···
 #include <linux/of_irq.h>
 #include <linux/pci.h>
 
-#include "pci.h"
+#include "../pci.h"
 
 #ifdef CONFIG_PCI_MSI
 

drivers/pci/msi/Makefile

···
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the PCI/MSI
+obj-$(CONFIG_PCI)		+= msi.o