arch/powerpc/cpu/mpc512x/pci.c: Fix GCC 4.6 warnings

Fix:
pci.c: In function 'pci_init_board':
pci.c:55:26: warning: variable 'pci_conf' set but not used
[-Wunused-but-set-variable]

Signed-off-by: Anatolij Gustschin <agust@denx.de>
diff --git a/arch/powerpc/cpu/mpc512x/pci.c b/arch/powerpc/cpu/mpc512x/pci.c
index 141db8b..16f034d 100644
--- a/arch/powerpc/cpu/mpc512x/pci.c
+++ b/arch/powerpc/cpu/mpc512x/pci.c
@@ -52,7 +52,6 @@
 	volatile law512x_t *pci_law;
 	volatile pot512x_t *pci_pot;
 	volatile pcictrl512x_t *pci_ctrl;
-	volatile pciconf512x_t *pci_conf;
 	u16 reg16;
 	u32 reg32;
 	u32 dev;
@@ -73,7 +72,6 @@
 	pci_law = im->sysconf.pcilaw;
 	pci_pot = im->ios.pot;
 	pci_ctrl = &im->pci_ctrl;
-	pci_conf = &im->pci_conf;
 
 	hose = &pci_hose;