counter: interrupt-cnt: Convert atomic_t -> atomic_long_t

counter: interrupt-cnt: Convert atomic_t -> atomic_long_t

Convert the internal counter type to atomic_long_t, which:
- doesn't change much for existing in-tree users as they are 32-bit anyway
  (stm32/i.MX6)
- doesn't introduce performace penalty on 32-bit platforms
- provides 64-bit resolution on 64-bit platforms with virtually no
  preformance penalty

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20250331152222.2263776-1-alexander.sverdlin@siemens.com
Signed-off-by: William Breathitt Gray <wbg@kernel.org>