Let's register restart handler for Exynos5440 from it's clock driver
for restart functionality. So that we can cleanup restart hooks from
machine specific file.

CC: Sylwester Nawrocki <s.nawrocki@samsung.com>
CC: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Pankaj Dubey <pankaj.dubey@samsung.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>