video: imx: Fix Makefile in order to be able to add other imx drivers

The IPUv3 is one IP part of the imx world, there are others, and
selecting the whole imx/ folder based on such a specific Kconfig symbol
is sub-optimal. Let's always enter the imx/ folder, and then selectively
compile parts of the folder based on the configuration.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
2 files changed