lynxpoint: Add Kconfig entry for Low Power chipset

There are enough subtle differences that it is useful to have
a Kconfig entry to differentiate the ULT/LP chipet from the
desktop/mobile versions.

Change-Id: I04ca1bc6f90bcf9e6994ea7125c98347e8def898
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/2645
Tested-by: build bot (Jenkins)
Reviewed-by: Marc Jones <marc.jones@se-eng.com>

src/southbridge/intel/lynxpoint/Kconfig

@@ -32,6 +32,12 @@ config SOUTH_BRIDGE_OPTIONS # dummy
 	select PCIEXP_COMMON_CLOCK
 	select SPI_FLASH
 
+config INTEL_LYNXPOINT_LP
+	bool
+	default n
+	help
+	  Set this option to y for Lynxpont LP (Haswell ULT).
+
 config EHCI_BAR
 	hex
 	default 0xfef00000