clocksource/drivers/sp804: Delete the leading "__" of some functions

Delete the leading "__" of __sp804_clocksource_and_sched_clock_init() and
__sp804_clockevents_init(), make it looks a little more comfortable.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200918132237.3552-4-thunder.leizhen@huawei.com