drm/i915/chv: Set soft reset override bit for data lane resets

The bits we've been setting so far only progagate the reset singal to
the data lanes. To actaully force the reset signal we need to set another
override bit.

v2: Fix mispalced ';' (Mika)

Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>