pci: mpc85xx: Add missing sync() after writing to PCI config space

On PowerPC we should use barrier after store operation to HW register.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Heiko Schocher <hs@denx.de>
Tested-by: Heiko Schocher <hs@denx.de>
diff --git a/drivers/pci/pci_mpc85xx.c b/drivers/pci/pci_mpc85xx.c
index 8a81a74..23f14db 100644
--- a/drivers/pci/pci_mpc85xx.c
+++ b/drivers/pci/pci_mpc85xx.c
@@ -41,6 +41,7 @@
 	out_be32(priv->cfg_addr, addr);
 	sync();
 	out_le32(priv->cfg_data, pci_conv_size_to_32(0, value, offset, size));
+	sync();
 
 	return 0;
 }