media: nxp: ignore unused suspend operations

media: nxp: ignore unused suspend operations

gcc warns about some functions being unused when CONFIG_PM_SLEEP
is disabled:

drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c:328:12: error: 'mxc_isi_pm_resume' defined but not used [-Werror=unused-function]
  328 | static int mxc_isi_pm_resume(struct device *dev)
      |            ^~~~~~~~~~~~~~~~~
drivers/media/platform/nxp/imx8-isi/imx8-isi-core.c:314:12: error: 'mxc_isi_pm_suspend' defined but not used [-Werror=unused-function]
  314 | static int mxc_isi_pm_suspend(struct device *dev)
      |            ^~~~~~~~~~~~~~~~~~

Use the modern SYSTEM_SLEEP_PM_OPS()/RUNTIME_PM_OPS() helpers in place
of the old SET_SYSTEM_SLEEP_PM_OPS()/SET_RUNTIME_PM_OPS() ones.

By convention, use pm_ptr() to guard the reference to the operations.
This makes no difference as long as the driver requires CONFIG_PM,
but is what users of SET_RUNTIME_PM_OPS() are supposed to do.

Fixes: cf21f328fcaf ("media: nxp: Add i.MX8 ISI driver")
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>