staging: media: tegra-video: move syncpt init/free to a per-soc op

tegra_channel_host1x_syncpt_init() gets the host1x syncpts needed for the
Tegra210 implementation, and tegra_channel_host1x_syncpts_free() puts
them.

Tegra20 needs to get and put a different syncpt. In preparation for adding
Tegra20 support, move these functions to new ops in the soc-specific
`struct tegra_vi_ops` .

No functional changes.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>