media: staging: media: imx: imx7-media-csi: Initialize locks early on

Group all the direct initialization of imx7_csi fields at the beginning
of the imx7_csi_probe() function instead of spreading them around.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>