media: v4l: fwnode: Read lane inversion information despite lane numbering

Read the lane inversion independently of whether the "data-lanes" property
exists. This makes sense since the caller may pass the number of lanes as
the default configuration while the lane inversion configuration may still
be available in firmware.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>