mb/google/rex: remove weak from cros gpio

No need for variant to use _weak.

BUG=b:276818954
TEST=new_variant_fulltest.sh rex0

Signed-off-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Change-Id: I7ad904e06e5d83edf4bc11cafd5060ca409bd4ae
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74294
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Ivy Jian <ivy.jian@quanta.corp-partner.google.com>

src/mainboard/google/rex/variants/rex0/gpio.c

@@ -440,4 +440,4 @@ static const struct cros_gpio cros_gpios[] = {
 	CROS_GPIO_WP_AH(GPIO_PCH_WP, CROS_GPIO_DEVICE_NAME),
 };
 
-DECLARE_WEAK_CROS_GPIOS(cros_gpios);
+DECLARE_CROS_GPIOS(cros_gpios);