rtc: rzn1: clear interrupts on remove

rtc: rzn1: clear interrupts on remove

It is good practice to clear running interrupts before removing the
driver. This is not really a bugfix because on current systems RuntimePM
will disable the module clock, so interrupts won't be initiated. The
dependency on that behaviour is subtle, though. Better be self-contained
and clean up when removing.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20250312100105.36767-2-wsa+renesas@sang-engineering.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>