[media] gspca_gl860: Clean up idxdata structs

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