arm: lpc32xx: phy3250 remove restart hook

Remove the restart hook assignment from phy3250;
this functionality is now managed by
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>