winsys/amdgpu: Close KMS handles for other DRM file descriptions

winsys/amdgpu: Close KMS handles for other DRM file descriptions

When a BO or amdgpu_screen_winsys is destroyed.

Should fix leaking such BOs in other DRM file descriptions.

v2:
* Pass the correct file descriptor to drmIoctl (Pierre-Eric
  Pelloux-Prayer)
* Use _mesa_hash_table_remove
v3:
* Close handles in amdgpu_winsys_unref as well
v4:
* Adapt to amdgpu_winsys::sws_list_lock.

Closes: https://gitlab.freedesktop.org/mesa/mesa/issues/2270
Fixes: 11a3679e3aba "winsys/amdgpu: Make KMS handles valid for original
                     DRM file descriptor"

Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3582>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3582>