dt-bindings: samsung,mipi-dsim: Add imx7d specific compatible

This add a imx7(d) specific compatible which is compatible to imx8mm.
This silences the dtbs_check warning:
arch/arm/boot/dts/nxp/imx/imx7s-mba7.dtb: dsi@30760000: compatible: 'oneOf' conditional failed, one must be fixed:
 ['fsl,imx7d-mipi-dsim', 'fsl,imx8mm-mipi-dsim'] is too long

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20250107094943.518474-3-alexander.stein@ew.tq-group.com


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>