drm/i915: Add main atomic entrypoints (v2)

Add the top-level atomic entrypoints for check/commit.  These won't get
called yet; we still need to either enable the atomic ioctl or switch to
using the non-transitional atomic helpers for legacy operations.

v2:
 - Use plane->pipe rather than plane->possible_crtcs while ensuring that
   only a single CRTC is in use.  Either way will work fine since i915
   drm_plane's are always tied to a single CRTC, but plane->pipe is
   slightly more intuitive. (Ander)
 - Simplify crtc/connector checking logic. (Ander)

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index 16e3dc3..c7e2ab5 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -66,6 +66,7 @@
 	  dvo_ns2501.o \
 	  dvo_sil164.o \
 	  dvo_tfp410.o \
+	  intel_atomic.o \
 	  intel_atomic_plane.o \
 	  intel_crt.o \
 	  intel_ddi.o \