media: imx: imx7-media-csi: Remove double reflash of DMA controller

The DMA controller needs to be reflashed after being configured. There
is however no need to do it twice, once in imx7_csi_configure() and once
in imx7_csi_sw_reset(), called from imx7_csi_enable(). Remove the
former.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Rui Miguel Silva <rmfrfs@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>