trogdor: Add third RAM_CODE pin

We decided to add a third RAM_CODE pin to the Trogdor family for devices
after rev1. This patch adds support to read it. Since the newly used pin
was previously unconnected (not pulled down) on rev1, this will change
the RAM_CODE result for previous versions (and actually make it
undetermined until we enable tri-state). But since we're not actually
using RAM_CODE for anything yet, and since those are development
revisions that will eventually be discontinued, this should be fine.

Signed-off-by: Julius Werner <jwerner@chromium.org>
Change-Id: I9b52982f17646a305b1a3e2c7d37606a7c38d0c4
Reviewed-on: https://review.coreboot.org/c/coreboot/+/40352
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Philip Chen <philipchen@google.com>
diff --git a/src/mainboard/google/trogdor/boardid.c b/src/mainboard/google/trogdor/boardid.c
index 9d92988..1b3a269 100644
--- a/src/mainboard/google/trogdor/boardid.c
+++ b/src/mainboard/google/trogdor/boardid.c
@@ -20,7 +20,7 @@
 {
 	static uint32_t id = UNDEFINED_STRAPPING_ID;
 
-	const gpio_t pins[] = {[1] = GPIO(91), [0] = GPIO(29)};
+	const gpio_t pins[] = {[2] = GPIO(13), [1] = GPIO(91), [0] = GPIO(29)};
 
 	if (id == UNDEFINED_STRAPPING_ID)
 		id = gpio_base2_value(pins, ARRAY_SIZE(pins));