media: tegra-video: Make tegra210_video_formats static

Fix the following sparse warning:

drivers/staging/media/tegra-video/tegra210.c:589:33: warning: symbol 'tegra210_video_formats' was not declared.

The tegra210_video_formats has only call site within tegra210.c
It should be static

Fixes: 423d10a99b30 ("media: tegra: Add Tegra210 Video input driver")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Samuel Zou <zou_wei@huawei.com>
Acked-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>