nb/intel/gm45: Enable LAPIC monotonic timer

Change-Id: I9f96561120d0feb44c5edd9e7241bc3456b31e5f
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/22221
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/northbridge/intel/gm45/Kconfig

@@ -21,6 +21,7 @@ if NORTHBRIDGE_INTEL_GM45
 config NORTHBRIDGE_SPECIFIC_OPTIONS # dummy
 	def_bool y
 	select HAVE_DEBUG_RAM_SETUP
+	select LAPIC_MONOTONIC_TIMER
 	select VGA
 	select INTEL_EDID
 	select INTEL_GMA_ACPI