media: v4l2-fwnode: Add helper to parse device properties

Add an helper function to parse common device properties in the same
way as v4l2_fwnode_endpoint_parse() parses common endpoint properties.

Parse the 'rotation' and 'orientation' properties from the firmware
interface.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>