In d7e81c2 (clocksource: Add clocksource_register_hz/khz interface) new
interfaces were added which simplify (and optimize) the selection of the
divisor shift/mult constants. Switch over to using this new interface.
Acked-by: Wan zongshun <mcuos.com@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>