media: i2c: imx290: fix conditional function defintions

The runtime suspend/resume functions are only referenced from the
dev_pm_ops, but they use the old SET_RUNTIME_PM_OPS() helper that
requires a __maybe_unused annotation to avoid a warning:

drivers/media/i2c/imx290.c:1082:12: error: unused function 'imx290_runtime_resume' [-Werror,-Wunused-function]
static int imx290_runtime_resume(struct device *dev)
^
drivers/media/i2c/imx290.c:1090:12: error: unused function 'imx290_runtime_suspend' [-Werror,-Wunused-function]
static int imx290_runtime_suspend(struct device *dev)
^

Convert this to the new RUNTIME_PM_OPS() helper that so this is not
required. To improve this further, also use the pm_ptr() helper that
lets the dev_pm_ops get dropped entirely when CONFIG_PM is disabled.

A related mistake happened in the of_match_ptr() macro here, which like
SET_RUNTIME_PM_OPS() requires the match table to be marked as
__maybe_unused, though I could not reproduce building this without
CONFIG_OF. Remove the of_match_ptr() here as there is no point in
dropping the match table in configurations without CONFIG_OF.

Fixes: 02852c01f654 ("media: i2c: imx290: Initialize runtime PM before subdev")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Reported-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Reviewed-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>