rtc: tps6586x: Fix initial enable_irq/disable_irq balance

Interrupts are automatically enabled when requested, so we need to
initialize irq_en accordingly to avoid causing an unbalanced enable
warning.

Signed-off-by: Esben Haabendal <esben@geanix.com>
Link: https://lore.kernel.org/r/20250516-rtc-uie-irq-fixes-v2-4-3de8e530a39e@geanix.com


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