rambi: export SPI write-protect GPIO correctly

Bay Trail has 3 banks of gpios. Therefore, in order to
properly identify a gpio the specific bank number as well
as the GPIO within that bank is needed. The SPI
write-protect GPIO is GPIO 6 within the SUS bank (offset
0x2000).

BUG=chrome-os-partner:24324
BUG=chrome-os-partner:24408
BRANCH=None
TEST=Built and booted. Looked at GPIO sysfs in the
     chromeos_acpi directory.

Change-Id: Ic51b5abe3bacf6cf9b6a90cf666f1a63b098a0e3
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/179195
Reviewed-on: http://review.coreboot.org/4995
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins)

src/mainboard/google/rambi/acpi/chromeos.asl

@@ -17,8 +17,20 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+/*
+ * Fields are in the following order.
+ * - Type: recovery = 1 developer mode = 2 write protect = 3
+ * - Active Level - if -1 not a valid gpio
+ * - GPIO number encoding - if -1 not a valid gpio
+ * - Chipset Name
+ *
+ * Note: On Bay Trail we need to encode gpios within the 3 separate banks
+ * with the MMIO offset of each banks space. e.g. GPIO_SUS[8] would be encoded
+ * as 0x2008 where the SUS offset (IO_BASE_OFFSET_GPSSUS) is 0x2000.
+ */
+
 Name(OIPG, Package() {
-	Package () { 0x0001, 0, 0xFF, "LynxPoint" }, // recovery
+	// No physical recovery button
-	Package () { 0x0002, 0, 0xFF, "LynxPoint" }, // developer
+	Package () { 0x0001, 0, 0xFFFFFFFF, "BayTrail" },
-	Package () { 0x0003, 0, 0xFF, "LynxPoint" }, // firmware write protect
+	Package () { 0x0003, 1, 0x2006, "BayTrail" },
 })