regulator: da9062: Make the use of IRQ optional

This patch makes the use of IRQ optional to make the DA9061/62 usable
for designs that don't have the IRQ pin connected, because the regulator
is usable without IRQ.

Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Reviewed-by: Adam Ward <DLG-Adam.Ward.opensource@dm.renesas.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Link: https://lore.kernel.org/r/20230713090328.3879-1-cniedermaier@dh-electronics.com


Signed-off-by: Mark Brown <broonie@kernel.org>