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-ip27.c b/arch/mips/pci/pci-ip27.c
index 193e949..0fbe4c0 100644
--- a/arch/mips/pci/pci-ip27.c
+++ b/arch/mips/pci/pci-ip27.c
@@ -50,7 +50,7 @@
 	bridge_t *bridge;
 	int slot;
 
-	pci_probe_only = 1;
+	pci_set_flags(PCI_PROBE_ONLY);
 
 	printk("a bridge\n");