baytrail: include mainboard's superio.asl

The mainboard needs an opportunity to hang devices off of
the LPC device. Therefore, provide this opportunity for the
mainboard.

BUG=chrome-os-partner:23505
BRANCH=None
TEST=Buit and booted with keyboard. Keys work.

Change-Id: Ie2b660ad43e86d9237b0b0bb0720b069670bc537
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/176133
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/4949
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/soc/intel/baytrail/acpi/lpc.asl

@@ -138,6 +138,9 @@ Device (LPCB)
 		})
 	}
 
+	// Include mainboard's superio.asl file.
+	#include "acpi/superio.asl"
+
 #ifdef ENABLE_TPM
 	Device (TPM)		// Trusted Platform Module
 	{