drm/ttm: Unexport ttm_global_swapout()

Unexport ttm_global_swapout() since it is not used outside of TTM.
Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230307144621.10748-5-thomas.hellstrom@linux.intel.com

drivers/gpu/drm/ttm/ttm_device.c

@@ -137,7 +137,6 @@ int ttm_global_swapout(struct ttm_operation_ctx *ctx, gfp_t gfp_flags)
 	mutex_unlock(&ttm_global_mutex);
 	return ret;
 }
-EXPORT_SYMBOL(ttm_global_swapout);
 
 int ttm_device_swapout(struct ttm_device *bdev, struct ttm_operation_ctx *ctx,
 		       gfp_t gfp_flags)