driver/pci: Fix compiling error

Fix compiling error in case CONFIG_SYS_PCIE2_MEM_VIRT or CONFIG_SYS_PCIE3_MEM_VIRT
not defined.

Signed-off-by: York Sun <yorksun@freescale.com>
Signed-off-by: Andy Fleming <afleming@freescale.com>
diff --git a/drivers/pci/fsl_pci_init.c b/drivers/pci/fsl_pci_init.c
index 20dabf3..86ccbe7 100644
--- a/drivers/pci/fsl_pci_init.c
+++ b/drivers/pci/fsl_pci_init.c
@@ -276,14 +276,18 @@
 		release_addr = CONFIG_SYS_PCIE1_MEM_VIRT
 			+ CONFIG_SRIO_PCIE_BOOT_BRR_OFFSET;
 		break;
+#ifdef CONFIG_SYS_PCIE2_MEM_VIRT
 	case 2:
 		release_addr = CONFIG_SYS_PCIE2_MEM_VIRT
 			+ CONFIG_SRIO_PCIE_BOOT_BRR_OFFSET;
 		break;
+#endif
+#ifdef CONFIG_SYS_PCIE3_MEM_VIRT
 	case 3:
 		release_addr = CONFIG_SYS_PCIE3_MEM_VIRT
 			+ CONFIG_SRIO_PCIE_BOOT_BRR_OFFSET;
 		break;
+#endif
 	default:
 		release_addr = 0;
 		break;