powerpc: Introduce ppc_pci_flags accessors

Currently there are a number of platforms that open code access to
the ppc_pci_flags global variable.  However, that variable is not
present if CONFIG_PCI is not set, which can lead to a build break.

This introduces a number of accessor functions that are defined
to be empty in the case of CONFIG_PCI being disabled.  The
various platform files in the kernel are updated to use these.

Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/sysdev/grackle.c b/arch/powerpc/sysdev/grackle.c
index d502927..5da37c2 100644
--- a/arch/powerpc/sysdev/grackle.c
+++ b/arch/powerpc/sysdev/grackle.c
@@ -57,7 +57,7 @@
 {
 	setup_indirect_pci(hose, 0xfec00000, 0xfee00000, 0);
 	if (machine_is_compatible("PowerMac1,1"))
-		ppc_pci_flags |= PPC_PCI_REASSIGN_ALL_BUS;
+		ppc_pci_add_flags(PPC_PCI_REASSIGN_ALL_BUS);
 	if (machine_is_compatible("AAPL,PowerBook1998"))
 		grackle_set_loop_snoop(hose, 1);
 #if 0	/* Disabled for now, HW problems ??? */