drm/tegra: Atomic conversion, phase 2

Hook up the default ->reset() and ->atomic_duplicate_state() helpers.
This ensures that state objects are properly created and framebuffer
reference counts correctly maintained.

Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/tegra/drm.c b/drivers/gpu/drm/tegra/drm.c
index 0e0da86..c1bb0d9 100644
--- a/drivers/gpu/drm/tegra/drm.c
+++ b/drivers/gpu/drm/tegra/drm.c
@@ -77,6 +77,8 @@
 	if (err < 0)
 		goto fbdev;
 
+	drm_mode_config_reset(drm);
+
 	/*
 	 * We don't use the drm_irq_install() helpers provided by the DRM
 	 * core, so we need to set this manually in order to allow the