mb/ocp/tiogapass: correct "POST complete" pad initial value

On OCP Tioga Pass the pad GPP_B20 is used as output for signalling "POST
complete" to the BMC. According to the schematics and the code in
`ramstage.c`, the signal is active-low. There is an external pull-up
resistor.

To make the signalling work as it should, set the initial output value
to `high`.

Change-Id: I82fbda1caba9163ba3b2e38f494a0cefa27e657f
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48670
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/ocp/tiogapass/include/tp_pch_gpio.h

@@ -99,7 +99,7 @@ static const struct pad_config gpio_table[] = {
 	/* GPP_B19 - GPIO */
 	PAD_CFG_GPO(GPP_B19, 1, DEEP),
 	/* GPP_B20 - GPIO */
-	PAD_CFG_GPO(GPP_B20, 0, DEEP),
+	PAD_CFG_GPO(GPP_B20, 1, DEEP),
 	/* GPP_B21 - GPIO */
 	PAD_CFG_GPI_TRIG_OWN(GPP_B21, NONE, DEEP, OFF, DRIVER),
 	/* GPP_B22 - GPIO */