arm: lpc32xx: remove restart handler

Remove the restart handler from "mach-lpc32xx";
this functionality is now available in the
pnx4008 watchdog driver.

Signed-off-by: Sylvain Lemieux <slemieux@tycoint.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>