clocksource/drivers/ixp4xx: Add driver

This adds a new slightly rewritten timer driver for the
Intel IXP4xx clocksource, clockevent and delay timer.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

include/linux/platform_data/timer-ixp4xx.h

@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __TIMER_IXP4XX_H
+#define __TIMER_IXP4XX_H
+
+#include <linux/ioport.h>
+
+void __init ixp4xx_timer_setup(resource_size_t timerbase,
+			       int timer_irq,
+			       unsigned int timer_freq);
+
+#endif