rtc: rv3029: avoid reading the status register uselessly

RV3029_STATUS is read in multiple location but its value is never used
afterwards. Avoid this register access when not necessary.

Link: https://lore.kernel.org/r/20191214221022.622482-6-alexandre.belloni@bootlin.com


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