device/pnp: add register PNP_IO4

Add the register PNP_IO4, which will be used by IT5570E in CB:48894.

Change-Id: Ic820295247323f546d4c48ed17cfa4eab3dc5e92
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48924
Reviewed-by:  Felix Singer <felixsinger@posteo.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/device/pnp_device.c b/src/device/pnp_device.c
index afe6948..259d449 100644
--- a/src/device/pnp_device.c
+++ b/src/device/pnp_device.c
@@ -249,6 +249,8 @@
 		pnp_get_ioresource(dev, PNP_IDX_IO2, info->io2);
 	if (info->flags & PNP_IO3)
 		pnp_get_ioresource(dev, PNP_IDX_IO3, info->io3);
+	if (info->flags & PNP_IO4)
+		pnp_get_ioresource(dev, PNP_IDX_IO4, info->io4);
 
 	if (info->flags & PNP_IRQ0) {
 		resource = new_resource(dev, PNP_IDX_IRQ0);