Revert "mb/aopen/dxplplusu: Remove board"

This reverts commit eb76a455cd39ec59b7f2ba28baeec9538befd59e
and applies minor fixes to make it build again.

PARALLEL_MP was working prior to board removal and no
relevant SMI handlers were implemented. So NO_SMM choice
is now selected.

Change-Id: Ia1cd02278240d1b5d006fb2a7730d3d86390f85b
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69339
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/src/southbridge/intel/i82801dx/chip.h b/src/southbridge/intel/i82801dx/chip.h
new file mode 100644
index 0000000..50f4f1c
--- /dev/null
+++ b/src/southbridge/intel/i82801dx/chip.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef I82801DX_CHIP_H
+#define I82801DX_CHIP_H
+
+#include <stdint.h>
+
+struct southbridge_intel_i82801dx_config {
+	int enable_usb;
+	int enable_native_ide;
+	/**
+	 * Interrupt Routing configuration
+	 * If bit7 is 1, the interrupt is disabled.
+	 */
+	uint8_t pirqa_routing;
+	uint8_t pirqb_routing;
+	uint8_t pirqc_routing;
+	uint8_t pirqd_routing;
+	uint8_t pirqe_routing;
+	uint8_t pirqf_routing;
+	uint8_t pirqg_routing;
+	uint8_t pirqh_routing;
+
+	uint8_t ide0_enable;
+	uint8_t ide1_enable;
+};
+
+#endif /* I82801DX_CHIP_H */