mb/google/skyrim: Fix Backlight GPIO

Backlight GPIO was set to HIGH, when it should have been set LOW to
enable the backlight in the embedded display.

BUG=b:224618411
TEST=load on Skyrim proto1, observe backlight

Signed-off-by: Jon Murphy <jpmurphy@google.com>
Change-Id: Ife3335ca5a3c2517a6817fccf0544e5fcacb1f9d
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63003
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/skyrim/variants/baseboard/gpio.c

@@ -61,7 +61,7 @@ static const struct soc_amd_gpio base_gpio_table[] = {
 	/* EN_PP3300_TCHSCR */
 	PAD_GPO(GPIO_29, HIGH),
 	/* SOC_DISABLE_DISP_BL */
-	PAD_GPO(GPIO_30, HIGH),
+	PAD_GPO(GPIO_30, LOW),
 	/* Unused */
 	PAD_NC(GPIO_31),
 	/* LPC_RST_L */