MIPS: Loongson: PCI: use existing mips_io_port_base

mips_io_port_base is initialized via set_io_port_base() in
arch/mips/lemote/lm2e/setup.c, we can use it directly here.
Signed-off-by: NWu Zhangjin <wuzj@lemote.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/lemote/lm2e/pci.c

@@ -84,10 +84,7 @@ static int __init pcibios_init(void)
 {
 	ict_pcimap();
 
-	loongson2e_pci_controller.io_map_base =
-	    (unsigned long) ioremap(LOONGSON2E_IO_PORT_BASE,
-				    loongson2e_pci_io_resource.end -
-				    loongson2e_pci_io_resource.start + 1);
+	loongson2e_pci_controller.io_map_base = mips_io_port_base;
 
 	register_pci_controller(&loongson2e_pci_controller);