gpu: add module.h to drivers/gpu files as required.

So that we don't get build failures once the implicit module.h
presence is removed.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/gpu/drm/radeon/ni.c b/drivers/gpu/drm/radeon/ni.c
index 556b7bc..fdb93f88 100644
--- a/drivers/gpu/drm/radeon/ni.c
+++ b/drivers/gpu/drm/radeon/ni.c
@@ -24,6 +24,7 @@
 #include <linux/firmware.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/module.h>
 #include "drmP.h"
 #include "radeon.h"
 #include "radeon_asic.h"