media: v4l: i2c: Replace "sensor-level" by "sensor"

A lot of sensor drivers are labelled as "sensor-level" drivers. That's
odd and somewhat confusing as the term isn't used elsewhere: these are
just sensor drivers. Call them such.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>