sh: Enable PCI66 support for SH7780 host controller.

This adds some helper glue for scanning the bus and determining if all
of the devices are 66MHz capable or not before flipping on 66MHz mode.
This isn't quite to spec, but it's fairly consistent with what other
embedded controllers end up having to do.

Scanning code cribbed from the MIPS txx9 PCI code.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/include/asm/pci.h b/arch/sh/include/asm/pci.h
index d124a00..5849d43 100644
--- a/arch/sh/include/asm/pci.h
+++ b/arch/sh/include/asm/pci.h
@@ -32,6 +32,8 @@
 };
 
 extern void register_pci_controller(struct pci_channel *hose);
+extern int pci_is_66mhz_capable(struct pci_channel *hose,
+				int top_bus, int current_bus);
 
 extern unsigned long PCIBIOS_MIN_IO, PCIBIOS_MIN_MEM;