mips: Vr41xx: add missing iounmap() on error in vr41xx_pciu_init()

add missing iounmap() of pciu_base on error when failed to init
io_map_base.

Signed-off-by: Qinglang Miao <[e-mail]>
Signed-off-by: Thomas Bogendoerfer <[e-mail]>

arch/mips/pci/pci-vr41xx.c

···
 		master = setup->master_io;
 		io_map_base = ioremap(master->bus_base_address,
 				      resource_size(res));
-		if (!io_map_base)
+		if (!io_map_base) {
+			iounmap(pciu_base);
 			return -EBUSY;
+		}
 
 		vr41xx_pci_controller.io_map_base = (unsigned long)io_map_base;
 	}