media: ipu-bridge: Only keep PLD around while parsing

There is no need to keep a reference to the PLD struct around,
it is only used once the get the sensor orientation.

Make ipu_bridge_parse_orientation() also get + put the PLD.

This is a preparation patch for making the ipu-bridge code more generic
so that it can be shared with the atomisp driver.

Reviewed-by: Andy Shevchenko <andy@kernel.org>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>