media: hantro: Check whether reset op is defined before use

[ Upstream commit 88d4b23a ]

The i.MX8MM/N/P does not define the .reset op since reset of the VPU is
done by genpd. Check whether the .reset op is defined before calling it
to avoid NULL pointer dereference.

Note that the Fixes tag is set to the commit which removed the reset op
from i.MX8M Hantro G2 implementation, this is because before this commit
all the implementations did define the .reset op.

Fixes: 6971efb7

 ("media: hantro: Allow i.MX8MQ G1 and G2 to run independently")
Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Tested-by: Chen-Yu Tsai <wenst@chromium.org>
Reviewed-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>