gpu: Add export.h as required to drivers/gpu files.

They need this to get all the EXPORT_SYMBOL variants and THIS_MODULE

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index fe39c35..3e927ce 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -30,6 +30,7 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/i2c.h>
+#include <linux/export.h>
 #include "drmP.h"
 #include "drm_edid.h"
 #include "drm_edid_modes.h"