media: imx8mq-mipi-csi2: Fix error code in imx8mq_mipi_csi_parse_dt()

This was returning IS_ERR() where PTR_ERR() was intended.

Fixes: 642b70d5 ("media: imx8mq-mipi-csi2: Add support for i.MX8QXP")
Cc: stable@vger.kernel.org
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Rui Miguel Silva <rui.silva@linaro.org>
Link: https://lore.kernel.org/r/9b6c7925-c9c4-44bd-acd5-1ef0e698eb87@sabinyo.mountain


Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>