[POWERPC] Pointers marked as __iomem do not need to be volatile

Fixes this warning:

arch/powerpc/platforms/powermac/pci.c: In function 'u3_ht_cfg_access':
arch/powerpc/platforms/powermac/pci.c:354: warning: return discards qualifiers from pointer target type
arch/powerpc/platforms/powermac/pci.c:358: warning: return discards qualifiers from pointer target type

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

include/asm-powerpc/pci-bridge.h

@@ -75,8 +75,8 @@ struct pci_controller {
 #endif
 
 	struct pci_ops *ops;
-	volatile unsigned int __iomem *cfg_addr;
-	volatile void __iomem *cfg_data;
+	unsigned int __iomem *cfg_addr;
+	void __iomem *cfg_data;
 
 #ifndef CONFIG_PPC64
 	/*