ARM: at91: don't use <mach/timex.h>

The platform specific <mach/timex.h> will be removed in a later patch.
So move its only still used symbol to a different header specific for
the only machine still using it. Also add a few explicit includes of
<mach/hardware.h> that are implicitly available through <mach/timex.h>.

Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

arch/arm/mach-at91/at91rm9200.c

@@ -21,6 +21,7 @@
 #include <mach/at91_pmc.h>
 #include <mach/at91_st.h>
 #include <mach/cpu.h>
+#include <mach/hardware.h>
 
 #include "at91_aic.h"
 #include "soc.h"