drm/tegra: sor: Set minor after debugfs initialization

The DRM minor is needed to teardown debugfs, so it needs to be tracked
to prevent a crash on driver removal.

Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/drm/tegra/sor.c b/drivers/gpu/drm/tegra/sor.c
index 7df7328..18b4d89 100644
--- a/drivers/gpu/drm/tegra/sor.c
+++ b/drivers/gpu/drm/tegra/sor.c
@@ -841,6 +841,8 @@
 		goto free;
 	}
 
+	sor->minor = minor;
+
 	return err;
 
 free: