media: aspeed: Fix dram hang at res-change

media: aspeed: Fix dram hang at res-change

Dram hang could happen in the steps below:
1. start capture/compression
2. out-of-lock watchdog raise irq because of res-change.
3. aspeed_video_irq_res_change do clk-off

At step3, capture/compression could be not accomplished yet. If clk-off
in the middle of video operation, dram controller could hang at ast2500.

Use reset rather than clk-off/on to avoid this problem.

Signed-off-by: Jammy Huang <jammy_huang@aspeedtech.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>