drm/atomic-helper: Remove redundant local var old_crtc_state in disable_outputs

drm/atomic-helper: Remove redundant local var old_crtc_state in disable_outputs

One of the two local variables old_crtc_state is redundantly defined in the
function disable_outputs().  It has only a scope partway through the block
for_each_connector_in_state.  So, let's remove it and use the one which
has the scope within the function disable_outputs().

Signed-off-by: Liu Ying <gnuiyl@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453088195-2564-1-git-send-email-gnuiyl@gmail.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>