[media] davinci/vpfe_capture: remove current_norm

Since vpfe_capture already provided a g_std op setting current_norm
does not actually do anything. Remove it.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Lad, Prabhakar <prabhakar.lad@ti.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>