radeon/vce: move feedback command inside of destroy function

On the CI family, firmware requires the destory command have to be the
last command in the IB, moving feedback command after destroy is causing
issues on CI cards, so we have to keep the previous logic that moves
destroy back to the last command.

But as the original issue fixed previously, with the newer family like Vega10,
feedback command have to be included inside of the task info command along
with destroy command.

Fixes: 6d74cb25("radeon/vce: move destroy command before feedback command")

Signed-off-by: Leo Liu <leo.liu@amd.com>
Acked-by: Christian König <christian.koenig@amd.com>
Cc: mesa-stable@lists.freedesktop.org
(cherry picked from commit c4de2f08)