[media] davinci: vpbe: replace V4L2_OUT_CAP_CUSTOM_TIMINGS with V4L2_OUT_CAP_DV_TIMINGS

This patch replaces V4L2_OUT_CAP_CUSTOM_TIMINGS macro with
V4L2_OUT_CAP_DV_TIMINGS. As V4L2_OUT_CAP_CUSTOM_TIMINGS is being phased
out.

Signed-off-by: Lad, Prabhakar <prabhakar.lad@ti.com>
Signed-off-by: Manjunath Hadli <manjunath.hadli@ti.com>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>