V4L/DVB (11374): v4l2-common: add v4l2_i2c_new_probed_subdev_addr

Add utility function to probe for a single address, rather than a list
of addresses.

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>