rtc: pm8xxx: rename alarm irq variable

Clean up the driver somewhat by renaming the driver-data alarm irq
variable by dropping the redundant "rtc" prefix.

Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Reviewed-by: David Collins <quic_collinsd@quicinc.com>
Link: https://lore.kernel.org/r/20230202155448.6715-11-johan+linaro@kernel.org


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