[media] saa6752hs: move to media/i2c

This driver is independent from saa7134, so there is no reason why this
shouldn't be in media/i2c like all other i2c media drivers.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>