[media] em28xx: add comment about Samsung and Kodak sensor probing addresses

The Windows driver also probes at least two further i2c addresses (0x22 >> 1
and 0x66 >> 1). I've got some hints that they are very likely used by Samsung
and Kodak sensors, which are known to be used in Empia devices, too.
We havn't seen any devices using these sensors yet and don't know how to probe
them properly, so leave a comment.

Signed-off-by: Frank Schäfer <fschaefer.oss@googlemail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>