[media] omap_vout: Set DSS overlay_info only if paddr is non zero

The omap_vout driver tries to set the DSS overlay_info using set_overlay_info()
when the physical address for the overlay is still not configured. This happens
in omap_vout_probe() and vidioc_s_fmt_vid_out().
The calls to omapvid_init(which internally calls set_overlay_info()) are removed
from these functions. They don't need to be called as the omap_vout_device
struct anyway maintains the overlay related changes made. Also, remove the
explicit call to set_overlay_info() in vidioc_streamon(), this was used to set
the paddr, this isn't needed as omapvid_init() does the same thing later.
These changes are required as the DSS2 driver since 3.3 kernel doesn't let you
set the overlay info with paddr as 0.

Signed-off-by: Archit Taneja <archit@ti.com>
Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>