[ARM SMP] Add timer/watchdog defines for MPCore

The timer/watchdog register definitions were missing from
the mpcore watchdog patch.  Add them.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/char/watchdog/mpcore_wdt.c

@@ -30,6 +30,8 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/device.h>
+
+#include <asm/hardware/arm_twd.h>
 #include <asm/uaccess.h>
 
 struct mpcore_wdt {