drm/i915/tv: Nuke silly 0 initialzation of xpos/ypos

Just assign the margin values directly to xpos/ypos instead
of first initializing to zero and then adding the values.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181112170000.27531-8-ville.syrjala@linux.intel.com


Reviewed-by: Imre Deak <imre.deak@intel.com>