[media] sta2x11: remove unused vars

Changeset 7b9f31f3 ("[media] sta2x11_vip: fix s_std") removed
autodetect code, but it kept two vars unused:

drivers/media/pci/sta2x11/sta2x11_vip.c: In function 'vidioc_s_std':
drivers/media/pci/sta2x11/sta2x11_vip.c:448:6: warning: unused variable 'status' [-Wunused-variable]
  int status;
      ^
drivers/media/pci/sta2x11/sta2x11_vip.c:447:14: warning: unused variable 'oldstd' [-Wunused-variable]
  v4l2_std_id oldstd = vip->std;
              ^
Remove them.

Fixes: 7b9f31f3 ("[media] sta2x11_vip: fix s_std")
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>