PCI/MSI: Enable PCI_MSI_IRQ_DOMAIN support for ARC

Add ARC as an arch that supports PCI_MSI_IRQ_DOMAIN and add generation of
msi.h in the ARC arch.

Signed-off-by: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
diff --git a/arch/arc/include/asm/Kbuild b/arch/arc/include/asm/Kbuild
index 0b10ef2..c332604 100644
--- a/arch/arc/include/asm/Kbuild
+++ b/arch/arc/include/asm/Kbuild
@@ -25,6 +25,7 @@
 generic-y += mm-arch-hooks.h
 generic-y += mman.h
 generic-y += msgbuf.h
+generic-y += msi.h
 generic-y += param.h
 generic-y += parport.h
 generic-y += pci.h