gpu: host1x: Cleanup includes

Most of the included files are either not required or already included
by some other header file.

Signed-off-by: Thierry Reding <treding@nvidia.com>
diff --git a/drivers/gpu/host1x/drm/dc.c b/drivers/gpu/host1x/drm/dc.c
index c4765b3..e11aec7 100644
--- a/drivers/gpu/host1x/drm/dc.c
+++ b/drivers/gpu/host1x/drm/dc.c
@@ -8,11 +8,8 @@
  */
 
 #include <linux/clk.h>
-#include <linux/debugfs.h>
-#include <linux/module.h>
-#include <linux/of.h>
-#include <linux/platform_device.h>
 #include <linux/clk/tegra.h>
+#include <linux/debugfs.h>
 
 #include "host1x_client.h"
 #include "dc.h"