Revert "drm/amdgpu: install stub fence into potential unused fence pointers"

This reverts commit 04bd3a36 which is
commit 187916e6 upstream.

It is reported to cause lots of log spam, so it should be dropped for
now.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/27d08b24-3581-4451-b8db-5df144784d6a@roeck-us.net


Reported-by: From: Chia-I Wu <olvaffe@gmail.com>
Link: https://lore.kernel.org/r/CAPaKu7RTgAMBLHbwtp4zgiBSDrTFtAj07k5qMzkuLQy2Zr+sZA@mail.gmail.com


Cc: Christian König <christian.koenig@amd.com>
Cc: Lang Yu <Lang.Yu@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>