media: ov7740: fix runtime pm initialization

media: ov7740: fix runtime pm initialization

The runtime PM of this device is enabled after v4l2_ctrl_handler_setup(),
and this makes this device's runtime PM usage count a negative value.

The ov7740_set_ctrl() tries to do something only if the device's runtime
PM usage counter is nonzero.

ov7740_set_ctrl()
{
	if (!pm_runtime_get_if_in_use(&client->dev))
		return 0;

	<do something>;

	pm_runtime_put(&client->dev);

	return ret;
}

However, the ov7740_set_ctrl() is called by v4l2_ctrl_handler_setup()
while the runtime PM of this device is not yet enabled.  In this case,
the pm_runtime_get_if_in_use() returns -EINVAL (!= 0).

Therefore we can't bail out of this function and the usage count is
decreased by pm_runtime_put() without increment.

This fixes this problem by enabling the runtime PM of this device before
v4l2_ctrl_handler_setup() so that the ov7740_set_ctrl() is always called
when the runtime PM is enabled.

Cc: Wenyou Yang <wenyou.yang@microchip.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Tested-by: Eugen Hristev <eugen.hristev@microchip.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>