mb/protectli/vault_kbl/mainboard.c: bring back the beep

This commit is cherry-picked from:
https://github.com/Dasharo/coreboot.git

Branch: protectli_vault_kbl/release

Original commit hash: b2b0a2bafbbe9be640f0fd0d02d85c81c90b796b

Then it was modified after code review, to:
* make it configurable
* remove code duplication

Signed-off-by: Purdea Andrei <andrei@purdea.ro>
Change-Id: I1350df3407aaa9b1fdaf9383972fac3a708bea96
Reviewed-on: https://review.coreboot.org/c/coreboot/+/88221
Reviewed-by: Alicja Michalska <ahplka19@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/protectli/vault_kbl/Kconfig

@@ -47,4 +47,12 @@ config CBFS_SIZE
 config USE_PM_ACPI_TIMER
 	default n
 
+config BEEP_ON_BOOT
+	bool "Beep on successful boot"
+	default y
+	help
+	  Make the platform beep using the PC speaker in final coreboot phase.
+	  May serve as a useful indicator in headless mode that platform is
+	  properly booting.
+
 endif

src/mainboard/protectli/vault_kbl/mainboard.c

@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <device/device.h>
+#include <pc80/i8254.h>
+
+static void mainboard_final(void *unused)
+{
+	if (CONFIG(BEEP_ON_BOOT))
+		beep(1500, 100);
+}
+
+struct chip_operations mainboard_ops = {
+	.final = mainboard_final,
+};