drm: Expose "FB_DAMAGE_CLIPS" property to atomic aware user-space only

Plane property "FB_DAMAGE_CLIPS" can only be used by atomic aware
user-space, so no point exposing it otherwise.

Cc: <stable@vger.kernel.org>
Signed-off-by: Deepak Rawat <drawat@vmware.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Fixes: d3b21767 ("drm: Add a new plane property to send damage during plane update")
Link: https://patchwork.freedesktop.org/patch/msgid/20190415172814.9840-1-drawat@vmware.com