amdgpu: fix GEM obj leak in amdgpu_display_user_framebuffer_create

This error code-path is missing a drm_gem_object_put call. Other
error code-paths are fine.

Signed-off-by: Simon Ser <contact@emersion.fr>
Fixes: 1769152 ("drm/amdgpu: Fail fb creation from imported dma-bufs. (v2)")
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Harry Wentland <hwentlan@amd.com>
Cc: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Cc: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

Author: emersion

drivers/gpu/drm/amd/amdgpu/amdgpu_display.c

@@ -986,6 +986,7 @@ amdgpu_display_user_framebuffer_create(struct drm_device *dev,
 	domains = amdgpu_display_supported_domains(drm_to_adev(dev), bo->flags);
 	if (obj->import_attach && !(domains & AMDGPU_GEM_DOMAIN_GTT)) {
 		drm_dbg_kms(dev, "Cannot create framebuffer from imported dma_buf\n");
+		drm_gem_object_put(obj);
 		return ERR_PTR(-EINVAL);
 	}