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/Kconfig b/src/southbridge/intel/i82801dx/Kconfig
new file mode 100644
index 0000000..98c1a47
--- /dev/null
+++ b/src/southbridge/intel/i82801dx/Kconfig
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config SOUTHBRIDGE_INTEL_I82801DX
+	bool
+	select ACPI_INTEL_HARDWARE_SLEEP_VALUES
+	select SOUTHBRIDGE_INTEL_COMMON_SMBUS
+	select SOUTHBRIDGE_INTEL_COMMON_EARLY_SMBUS
+	select SOUTHBRIDGE_INTEL_COMMON_RTC
+	select SOUTHBRIDGE_INTEL_COMMON_RESET
+	select SOUTHBRIDGE_INTEL_COMMON_USB_DEBUG
+	select HAVE_POWER_STATE_AFTER_FAILURE
+	select HAVE_POWER_STATE_PREVIOUS_AFTER_FAILURE
+	select BOOT_DEVICE_NOT_SPI_FLASH
+
+if SOUTHBRIDGE_INTEL_I82801DX
+
+config EHCI_BAR
+	hex
+	default 0xfef00000
+
+endif