drm/mgag200: Do not include <linux/export.h>

Fix the compile-time warning

  drivers/gpu/drm/mgag200/mgag200_ddc.c: warning: EXPORT_SYMBOL() is not used, but #include <linux/export.h> is present

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://lore.kernel.org/r/20250612085308.203861-1-tzimmermann@suse.de

Author: tdz

drivers/gpu/drm/mgag200/mgag200_ddc.c

@@ -26,7 +26,6 @@
  * Authors: Dave Airlie <airlied@redhat.com>
  */
 
-#include <linux/export.h>
 #include <linux/i2c-algo-bit.h>
 #include <linux/i2c.h>
 #include <linux/pci.h>