media: imx/Kconfig: add depends on HAS_DMA

Add missing dependency.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Steve Longerbeam <steve_longerbeam@mentor.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>