[ Upstream commit e4337877 ]

When allocation for mdp5_kms fails, calling mdp5_destroy() leads to undefined
behaviour, likely a nullptr exception or use-after-free troubles.
Signed-off-by: Roy Spliet <nouveau@spliet.org>
Reviewed-by: Abhinav Kumar <abhinavk@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>