media: sun4i: Make sun4i_csi_formats static

The sun4i_csi_formats array is only used in sun4i_v4l2.c, so it doesn't
make any sense to have it !static.

[Sakari Ailus: const static -> static const]

Reported-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>