media: ov5647: Apply controls only when powered

Use pm_runtime_get_if_in_use() in s_ctrl to apply controls
only when the device is powered on.

Rework the control set function to balance the
pm_runtime_get_if_in_use() call with
pm_runtime_put() at the end of the function.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>