media: dt-bindings: media: nxp,imx-mipi-csi2: i.MX8MP support

The CSIS CSI-2 receiver in the i.MX8MP seems to be identical to the
version present in the i.MX8MM. Add a device-specific compatible string,
with a fallback to the i.MX8MM compatible.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>