mb/google/rex: Correct EC-is-trusted logic

Fix EC_IN_RW config for Rex. Dauntless on Rex does not have an EC_IN_RW GPIO pin.

Port of commit 7f339c6050 ("mb/google/corsola: Correct EC-is-trusted logic")

BUG=b:243950850
TEST=Built and booted to Google Rex.

Signed-off-by: Kapil Porwal <kapilporwal@google.com>
Change-Id: I97e5c752b4f36c9221137903f755837880f6b1c4
Reviewed-on: https://review.coreboot.org/c/coreboot/+/67208
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Tarun Tuli <taruntuli@google.com>

src/mainboard/google/rex/chromeos.c

@@ -12,7 +12,7 @@ void fill_lb_gpios(struct lb_gpios *gpios)
 		{-1, ACTIVE_HIGH, get_lid_switch(), "lid"},
 		{-1, ACTIVE_HIGH, 0, "power"},
 		{-1, ACTIVE_HIGH, gfx_get_init_done(), "oprom"},
-		{GPIO_EC_IN_RW, ACTIVE_HIGH, gpio_get(GPIO_EC_IN_RW), "EC in RW"},
+		{-1, ACTIVE_HIGH, 0, "EC in RW"},
 	};
 	lb_add_gpios(gpios, chromeos_gpios, ARRAY_SIZE(chromeos_gpios));
 }
@@ -24,6 +24,6 @@ int get_write_protect_state(void)
 
 int get_ec_is_trusted(void)
 {
-	/* EC is trusted if not in RW. */
-	return !gpio_get(GPIO_EC_IN_RW);
+	/* VB2_CONTEXT_EC_TRUSTED should be set according to the Ti50 boot mode. */
+	return 0;
 }

src/mainboard/google/rex/variants/baseboard/rex/include/baseboard/gpio.h

@@ -9,8 +9,6 @@
 /* Fixme: Update proper GPIO number based on schematics */
 /* WP signal to PCH */
 #define GPIO_PCH_WP	GPP_H10
-/* EC in RW or RO */
-#define GPIO_EC_IN_RW	0
 /* GPIO IRQ for tight timestamps / wake support */
 #define EC_SYNC_IRQ	GPP_A17_IRQ
 /* eSPI virtual wire reporting */