soc/intel/apollolake: Implement _PIC method into ACPI

The _PIC method is called by the OS to choose between interrupt routing
via the i8259 interrupt controller or the APIC.

Change-Id: I2bc16f9c096c095c02de3692e76c0906cec54cb5
Signed-off-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Reviewed-on: https://review.coreboot.org/20617
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/intel/apollolake/acpi/platform.asl

@@ -18,3 +18,19 @@
 /* Enable ACPI _SWS methods */
 #include <soc/intel/common/acpi/acpi_wake_source.asl>
 #include <soc/intel/common/acpi/platform.asl>
+
+Name(\PICM, Zero) // IOAPIC/8259
+
+/*
+ * The _PIC method is called by the OS to choose between interrupt
+ * routing via the i8259 interrupt controller or the APIC.
+ *
+ * _PIC is called with a parameter of 0 for i8259 configuration and
+ * with a parameter of 1 for Local Apic/IOAPIC configuration.
+ */
+
+Method (_PIC, 1)
+{
+	/* Remember the OS' IRQ routing choice. */
+	Store (Arg0, PICM)
+}