drm/tegra: Atomic conversion, phase 1

Implement initial atomic state handling. Hook up the CRTCs, planes' and
connectors' ->atomic_destroy_state() callback to ensure that the atomic
state objects don't leak.

Furthermore the CRTC now implements the ->mode_set_nofb() callback that
is used by new helpers to implement ->mode_set() and ->mode_set_base().
These new helpers also make use of the new plane helper functions which
the driver now provides.

Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/tegra/hdmi.c b/drivers/gpu/drm/tegra/hdmi.c
index d41530f..bf868d5 100644
--- a/drivers/gpu/drm/tegra/hdmi.c
+++ b/drivers/gpu/drm/tegra/hdmi.c
@@ -14,6 +14,7 @@
 #include <linux/regulator/consumer.h>
 #include <linux/reset.h>
 
+#include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_crtc_helper.h>
 
@@ -781,6 +782,7 @@
 	.detect = tegra_output_connector_detect,
 	.fill_modes = drm_helper_probe_single_connector_modes,
 	.destroy = tegra_output_connector_destroy,
+	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
 };
 
 static enum drm_mode_status