[media] gspca - stv06xx: Fix a regression with the bridge/sensor vv6410

Setting the H and V flip controls at webcam connection time prevents
the webcam to work correctly.
This patch checks if the webcam is streaming before setting the flips.
It does not set the flips (nor other controls) at webcam start time.

Tested-by: Philippe ROUBACH <philippe.roubach@free.fr>
Signed-off-by: Jean-François Moine <moinejf@free.fr>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>