chromeos mainboards: remove chromeos.asl

Use the ACPI generator for creating the Chrome OS gpio
package. Each mainboard has its own list of Chrome OS
gpios that are fed into a helper to generate the ACPI
external OIPG package.  Additionally, the common
chromeos.asl is now conditionally included based on
CONFIG_CHROMEOS.

Change-Id: I1d3d951964374a9d43521879d4c265fa513920d2
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/15909
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>

src/mainboard/intel/kunimitsu/chromeos.c

@@ -82,3 +82,13 @@ int get_write_protect_state(void)
 	/* Read PCH_WP GPIO. */
 	return gpio_get(GPIO_PCH_WP);
 }
+
+static const struct cros_gpio cros_gpios[] = {
+	CROS_GPIO_REC_AL(CROS_GPIO_VIRTUAL, CROS_GPIO_DEVICE_NAME),
+	CROS_GPIO_WP_AH(GPIO_PCH_WP, CROS_GPIO_DEVICE_NAME),
+};
+
+void mainboard_chromeos_acpi_generate(void)
+{
+	chromeos_acpi_gpio_generate(cros_gpios, ARRAY_SIZE(cros_gpios));
+}