powerpc/pci: Reduce log level of PCI I/O space warning

If a PHB has no I/O space, there's no need to make it look like
something bad happened, a pr_debug() is plenty enough since this
is the case of all our modern POWER chips.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/pci-common.c

@@ -1497,7 +1497,7 @@ static void pcibios_setup_phb_resources(struct pci_controller *hose,
 	res = &hose->io_resource;
 
 	if (!res->flags) {
-		pr_info("PCI: I/O resource not set for host"
+		pr_debug("PCI: I/O resource not set for host"
 			 " bridge %s (domain %d)\n",
 			 hose->dn->full_name, hose->global_number);
 	} else {