rtc: ingenic: Remove unused fields from private structure

The 'clk' and 'irq' fields were only ever used in the probe function.
Therefore they can be moved to be simple local variables of the probe
function.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20200505221336.222313-5-paul@crapouillou.net


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>