media: vimc: remove EXPORT_SYMBOL_GPL declarations

vimc is a single kernel module and does not need to
export any symbols therefore there is no need for these
declarations.

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>