[media] platform: compile VIDEO_CODA with COMPILE_TEST

Currently, IMX_VDOA and VIDEO_CODA only builds on ARCH_MXC.

That prevented me to build-test the driver, causing a bad patch
to be applied, and to see other warnings on this driver.

Hans wrote a similar patch, but his version was fold with a
warning fixup hunk.
So, I opted to keep my version.

Reported-by: Russell King <linux@armlinux.org.uk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by Hans Verkuil <hans.verkuil@cisco.com>
Acked-by Philipp Zabel <p.zabel@pengutronix.de>