drm: Make drm_atomic.h standalone includible

This header file makes use of a bunch of structures declared in the
drm_crtc.h header file. Include that to make sure the drm_atomic.h
header can be included standalone.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

include/drm/drm_atomic.h

@@ -28,6 +28,8 @@
 #ifndef DRM_ATOMIC_H_
 #define DRM_ATOMIC_H_
 
+#include <drm/drm_crtc.h>
+
 struct drm_atomic_state * __must_check
 drm_atomic_state_alloc(struct drm_device *dev);
 void drm_atomic_state_clear(struct drm_atomic_state *state);