powerpc/PCI: replace pci_probe_only with pci_flags

We already use pci_flags, so this just sets pci_flags directly and removes
the intermediate step of figuring out pci_probe_only, then using it to set
pci_flags.

The PCI core provides a pci_flags definition (currently __weak), so drop
the powerpc definitions in favor of that.

CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

arch/powerpc/platforms/pseries/setup.c

@@ -380,8 +380,8 @@ static void __init pSeries_setup_arch(void)
 
 	fwnmi_init();
 
-	/* By default, only probe PCI (can be overriden by rtas_pci */
-	pci_probe_only = 1;
+	/* By default, only probe PCI (can be overriden by rtas_pci) */
+	pci_add_flags(PCI_PROBE_ONLY);
 
 	/* Find and initialize PCI host bridges */
 	init_pci_config_tokens();