rtc: max31335: use regmap_update_bits_check

Simplify the IRQ handler by using regmap_update_bits_check.

Reviewed-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Link: https://lore.kernel.org/r/20240115232215.273374-2-alexandre.belloni@bootlin.com


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