media: ipu-bridge: Add a parse_sensor_fwnode callback to ipu_bridge_init()

Add a parse_sensor_fwnode() callback to ipu_bridge_init(), so that
ipu_bridge_init() can be used with other sensor fwnode parse functions
then just ipu_bridge_parse_ssdb().

This will allow the ipu3-bridge code to also be used by the atomisp
driver.

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