[media] gspca_gl860: Clean up idxdata structs

Signed-off-by: Ismael Luceno <ismael.luceno@gmail.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>