rtc: sun6i: Don't reference clk_init_data after registration

rtc: sun6i: Don't reference clk_init_data after registration

A future patch is going to change semantics of clk_register() so that
clk_hw::init is guaranteed to be NULL after a clk is registered. Avoid
referencing this member here so that we don't run into NULL pointer
exceptions.

Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lkml.kernel.org/r/20190815160020.183334-4-sboyd@kernel.org
Acked-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>