sparc/PCI: register busn_res for root buses

Add the host bridge bus number aperture to the resource list.
Like the MMIO and I/O port apertures, this is used when assigning
resources to hot-added devices or in the case of conflicts.

[bhelgaas: changelog, fix "pci_last_busn" typo]
Acked-by: "David S. Miller" <davem@davemloft.net>
CC: sparclinux@vger.kernel.org
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/arch/sparc/kernel/pci_impl.h b/arch/sparc/kernel/pci_impl.h
index 6beb60d..918a203 100644
--- a/arch/sparc/kernel/pci_impl.h
+++ b/arch/sparc/kernel/pci_impl.h
@@ -97,6 +97,7 @@
 	/* PBM I/O and Memory space resources. */
 	struct resource			io_space;
 	struct resource			mem_space;
+	struct resource			busn;
 
 	/* Base of PCI Config space, can be per-PBM or shared. */
 	unsigned long			config_space;