sb/intel/common: Create a common implementation of acpi_fill_madt()

The function `acpi_fill_madt()` is identical among all the Lynx Point
boards and sb/intel/bd82x6x, so share a common function between them.

Earlier Intel platforms have similar implementations of this function.
The common implementation might only need minor alterations to support
them.

Tested on an ASRock H81M-HDS and Google Peppy (variant of Slippy). No
issues arose from this patch.

Change-Id: Ife9e3917febf43d8a92cac66b502e2dee8527556
Signed-off-by: Tristan Corrick <tristan@corrick.kiwi>
Reviewed-on: https://review.coreboot.org/29388
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

src/southbridge/intel/common/Kconfig

@@ -30,6 +30,9 @@ config HAVE_INTEL_CHIPSET_LOCKDOWN
 config SOUTHBRIDGE_INTEL_COMMON_SMM
 	def_bool n
 
+config SOUTHBRIDGE_INTEL_COMMON_ACPI_MADT
+	bool
+
 config INTEL_DESCRIPTOR_MODE_CAPABLE
 	def_bool n
 	help