drm/gud: Fix missing include

Add missing vmalloc.h include.

Fixes: c17d0486 ("drm/gud: Use the shadow plane helper")
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20221207-gud-missing-include-v1-0-c5b32c9c59da@tronnes.org

drivers/gpu/drm/gud/gud_pipe.c

@@ -5,6 +5,7 @@
 
 #include <linux/lz4.h>
 #include <linux/usb.h>
+#include <linux/vmalloc.h>
 #include <linux/workqueue.h>
 
 #include <drm/drm_atomic.h>