mips/PCI: replace pci_probe_only with pci_flags

Some architectures (alpha, mips, powerpc) have an arch-specific
"pci_probe_only" flag.  Others use PCI_PROBE_ONLY in pci_flags for
the same purpose.  This moves mips to the pci_flags approach so
generic code can use the same test across all architectures.

CC: Ralf Baechle <ralf@linux-mips.org>
CC: linux-mips@linux-mips.org
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
diff --git a/arch/mips/pci/pci-xlr.c b/arch/mips/pci/pci-xlr.c
index 3d701a9..1644805 100644
--- a/arch/mips/pci/pci-xlr.c
+++ b/arch/mips/pci/pci-xlr.c
@@ -292,7 +292,7 @@
 static int __init pcibios_init(void)
 {
 	/* PSB assigns PCI resources */
-	pci_probe_only = 1;
+	pci_set_flags(PCI_PROBE_ONLY);
 	pci_config_base = ioremap(DEFAULT_PCI_CONFIG_BASE, 16 << 20);
 
 	/* Extend IO port for memory mapped io */