hwmon: (ina3221) Use DEFINE_RUNTIME_DEV_PM_OPS() and pm_ptr()

These new macros allow the compiler to see all the functions even if
!CONFIG_PM* and remove the structures and functions if unused.
This removes the need for __maybe_unused markings.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Ninad Malwade <nmalwade@nvidia.com>
Link: https://lore.kernel.org/r/20220925172759.3573439-19-jic23@kernel.org


Signed-off-by: Guenter Roeck <linux@roeck-us.net>