soc/apollolake: Add UART0

In my case, on UPsquared board with Celeron N3350 CPU,
I don't have UART2 but UART0.

Change-Id: Id9a742144eba0f1d1544aafecf44d4730d055b4a
Signed-off-by: Felix Singer <felix.singer@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31864
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

src/soc/intel/apollolake/uart.c

@@ -48,6 +48,13 @@ const struct uart_gpio_pad_config uart_gpio_pads[] = {
 		},
 	},
 #else
+	{
+		.console_index = 0,
+		.gpios = {
+			PAD_CFG_NF(GPIO_38, NATIVE, DEEP, NF1), /* UART0 RX */
+			PAD_CFG_NF(GPIO_39, NATIVE, DEEP, NF1), /* UART0 TX */
+		},
+	},
 	{
 		.console_index = 1,
 		.gpios = {