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/include/asm/pci.h b/arch/powerpc/include/asm/pci.h
index 1c721a6..3548159 100644
--- a/arch/powerpc/include/asm/pci.h
+++ b/arch/powerpc/include/asm/pci.h
@@ -38,8 +38,8 @@
  * Set this to 1 if you want the kernel to re-assign all PCI
  * bus numbers (don't do that on ppc64 yet !)
  */
-#define pcibios_assign_all_busses()    	(ppc_pci_flags & \
-					 PPC_PCI_REASSIGN_ALL_BUS)
+#define pcibios_assign_all_busses() \
+	(ppc_pci_has_flag(PPC_PCI_REASSIGN_ALL_BUS))
 #define pcibios_scan_all_fns(a, b)	0
 
 static inline void pcibios_set_master(struct pci_dev *dev)