[POWERPC] PowerPC MSI infrastructure

This provides the architecture specific hooks to support MSI on
powerpc.  We implement the newly added arch_setup_msi_irqs() and
arch_teardown_msi_irqs(), and then delegate to ppc_md routines.

Platforms that don't implement MSI will leave the ppc_md calls blank,
arch_msi_check_device() will detect this and return ENOSYS. Drivers
should detect this error and continue to use LSI.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 94c703a..3e779f0 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -68,6 +68,7 @@
 pci64-$(CONFIG_PPC64)		+= pci_64.o pci_dn.o
 pci32-$(CONFIG_PPC32)		:= pci_32.o
 obj-$(CONFIG_PCI)		+= $(pci64-y) $(pci32-y)
+obj-$(CONFIG_PCI_MSI)		+= msi.o
 kexec-$(CONFIG_PPC64)		:= machine_kexec_64.o
 kexec-$(CONFIG_PPC32)		:= machine_kexec_32.o
 obj-$(CONFIG_KEXEC)		+= machine_kexec.o crash.o $(kexec-y)