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/r100.c b/drivers/gpu/drm/radeon/r100.c
index 8f8b8fa..cbf49f4 100644
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -41,6 +41,7 @@
 
 #include <linux/firmware.h>
 #include <linux/platform_device.h>
+#include <linux/module.h>
 
 #include "r100_reg_safe.h"
 #include "rn50_reg_safe.h"