Revert "mb/clevo/kbl-u: drop duplicated configuration of UART pads"

This reverts commit ccceb2250e.

Reason for revert:
UART pad configuration should not be done in common code, since it
could cause short circuits if the user configures a wrong UART index.

Change-Id: Idc268debc60a027ed2f5a76e0de8ea2d1cde0fc4
Signed-off-by: Felix Singer <felixsinger@posteo.net>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48327
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Michael Niewöhner <foss@mniewoehner.de>

src/mainboard/clevo/kbl-u/Makefile.inc

@@ -2,6 +2,9 @@
 
 CPPFLAGS_common += -I$(src)/mainboard/$(MAINBOARDDIR)/include
 
+bootblock-y += bootblock.c
+bootblock-y += variants/$(VARIANT_DIR)/gpio_early.c
+
 ramstage-y += ramstage.c
 ramstage-y += variants/$(VARIANT_DIR)/hda_verb.c
 ramstage-y += variants/$(VARIANT_DIR)/gpio.c

src/mainboard/clevo/kbl-u/bootblock.c

@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <bootblock_common.h>
+#include <variant/gpio.h>
+
+void bootblock_mainboard_early_init(void)
+{
+	variant_configure_early_gpios();
+}

src/mainboard/clevo/kbl-u/include/variant/gpio.h

@@ -3,6 +3,7 @@
 #ifndef VARIANT_GPIO_H
 #define VARIANT_GPIO_H
 
+void variant_configure_early_gpios(void);
 void variant_configure_gpios(void);
 
 #endif

src/mainboard/clevo/kbl-u/variants/n13xwu/gpio_early.c

@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <soc/gpio.h>
+#include <variant/gpio.h>
+
+static const struct pad_config early_gpio_table[] = {
+	// UART2_RXD
+	_PAD_CFG_STRUCT(GPP_C20,	0x44000702,	0x0),
+
+	// UART2_TXD
+	_PAD_CFG_STRUCT(GPP_C21,	0x44000700,	0x0)
+};
+
+void variant_configure_early_gpios(void)
+{
+	gpio_configure_pads(early_gpio_table, ARRAY_SIZE(early_gpio_table));
+}