media: i2c/Kconfig: reorganize items there

Right now, there are I2C drivers that don't depend on
camera support before and after those.

Move the camera support drivers to the end, and add
a notice at the "endif", in order to make easier to
maintain and to avoid adding extra dependencies at
the other i2c/*/Kconfig files.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>