sb,soc/intel: Add HPTS() for HPET visibility

Based on the detected OS the HPET ACPI device needs to
be hidden sometimes.

Change-Id: I4c6f87f30ea0de5c073b1fcf57794bb9e19d4d91
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49483
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/southbridge/intel/common/acpi/platform.asl

@@ -76,3 +76,19 @@ Method(GOS, 0)
 		}
 	}
 }
+
+/* Arg0 is state of HPET hardware enablement. */
+Method (HPTS, 1)
+{
+	/* HPET hardware disabled. */
+	If (!Arg0) {
+		Return (0x0)
+	}
+
+	/* Ancient versions of Windows don't want to see the HPET. */
+	If (OSYS < 2001) {
+		Return (0xb)
+	}
+
+	Return (0xf)
+}