media: vimc: move duplicated IS_SRC and IS_SINK to common header

Move duplicated IS_SRC and IS_SINK dfines to common header. Rename
them to VIMC_IS_SRC and VIM_IS_SINK.

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Helen Koike <helen.koike@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>