ACPI: Move common _PIC method

Change-Id: I659835354570fb1d4860fcbddf2a51831170a374
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50470
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

src/acpi/dsdt_top.asl

@@ -16,3 +16,17 @@ Name (PICM, Zero)
 
 /* Power state (AC = 1) */
 Name (PWRS, One)
+
+/*
+ * 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. */
+	PICM = Arg0
+}