media: imx: Compile imx6-media-objs only for CONFIG_VIDEO_IMX_CSI

imx6-media-objs contains a set of objects that are specific to the i.MX6
IPU-based media subsystem. They're not needed for the i.MX7 CSI. Only
compile them if CONFIG_VIDEO_IMX_CSI is selected.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Rui Miguel Silva <rmfrfs@gmail.com>
Reviewed-by: Ezequiel Garcia <ezequiel@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/imx/Makefile

 # SPDX-License-Identifier: GPL-2.0
+imx-media-common-objs := imx-media-capture.o imx-media-dev-common.o \
+	imx-media-of.o imx-media-utils.o
+
 imx6-media-objs := imx-media-dev.o imx-media-internal-sd.o \
 	imx-ic-common.o imx-ic-prp.o imx-ic-prpencvf.o imx-media-vdic.o \
 	imx-media-csc-scaler.o
 
-imx-media-common-objs := imx-media-capture.o imx-media-dev-common.o \
-	imx-media-of.o imx-media-utils.o
-
 imx6-media-csi-objs := imx-media-csi.o imx-media-fim.o
 
 obj-$(CONFIG_VIDEO_IMX_MEDIA) += imx-media-common.o