for_each_obj_in_state is about to be removed, so convert
to the new iterator macros.

Just like in omap, use crtc_state->active instead of
crtc_state->enable when waiting for completion.

Changes since v1:
- Fix compilation.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Archit Taneja <architt@codeaurora.org>
Cc: Vincent Abriou <vincent.abriou@st.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Rob Herring <robh@kernel.org>
Cc: Markus Elfring <elfring@users.sourceforge.net>
Cc: Sushmita Susheelendra <ssusheel@codeaurora.org>
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Archit Taneja <architt@codeaurora.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20170719143920.25685-6-maarten.lankhorst@linux.intel.com