drm/exynos: remove call to drm_gem_free_mmap_offset()

The drm_gem_object_release() function already performs this cleanup,
so there is no reason to do it explicitly.
Signed-off-by: NJoonyoung Shim <jy0922.shim@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_drm_gem.c

@@ -152,8 +152,6 @@ void exynos_drm_gem_destroy(struct exynos_drm_gem_obj *exynos_gem_obj)
 	else
 		exynos_drm_free_buf(exynos_gem_obj);
 
-	drm_gem_free_mmap_offset(obj);
-
 	/* release file pointer to gem object. */
 	drm_gem_object_release(obj);
 
@@ -530,7 +528,6 @@ int exynos_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma)
 
 err_close_vm:
 	drm_gem_vm_close(vma);
-	drm_gem_free_mmap_offset(obj);
 
 	return ret;
 }