ARM: drop <mach/timex.h> for !ARCH_MULTIPLATFORM, too

While <mach/timex.h> isn't used for multi-platform builds since long it
still is for "normal" builds. As the previous patches fix all sites to
not make use of this per-platform file, it can go now for good also for
platforms that are not (yet) converted to multi-platform.

While at it there are no users of CLOCK_TICK_RATE any more, so also drop
the dummy #define.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

arch/arm/mach-pxa/include/mach/timex.h

@@ -1,34 +0,0 @@
-/*
- * arch/arm/mach-pxa/include/mach/timex.h
- *
- * Author:	Nicolas Pitre
- * Created:	Jun 15, 2001
- * Copyright:	MontaVista Software Inc.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-/* Various drivers are still using the constant of CLOCK_TICK_RATE, for
- * those drivers to at least work, the definition is provided here.
- *
- * NOTE: this is no longer accurate when multiple processors and boards
- * are selected, newer drivers should not depend on this any more.  Use
- * either the clocksource/clockevent or get this at run-time by calling
- * get_clock_tick_rate() (as defined in generic.c).
- */
-
-#if defined(CONFIG_PXA25x)
-/* PXA250/210 timer base */
-#define CLOCK_TICK_RATE 3686400
-#elif defined(CONFIG_PXA27x)
-/* PXA27x timer base */
-#ifdef CONFIG_MACH_MAINSTONE
-#define CLOCK_TICK_RATE 3249600
-#else
-#define CLOCK_TICK_RATE 3250000
-#endif
-#else
-#define CLOCK_TICK_RATE 3250000
-#endif