dt-bindings: display: exynos: dsim: Add NXP i.MX8M Plus support

Samsung MIPI DSIM bridge can also be found in i.MX8M Plus SoC.

Add dt-bingings for it.
Reviewed-by: Marek Vasut <marex@denx.de>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

Documentation/devicetree/bindings/display/exynos/exynos_dsim.txt

@@ -8,6 +8,7 @@ Required properties:
 		"samsung,exynos5422-mipi-dsi" /* for Exynos5422/5800 SoCs */
 		"samsung,exynos5433-mipi-dsi" /* for Exynos5433 SoCs */
 		"fsl,imx8mm-mipi-dsim" /* for i.MX8M Mini/Nano SoCs */
+		"fsl,imx8mp-mipi-dsim" /* for i.MX8M Plus SoCs */
   - reg: physical base address and length of the registers set for the device
   - interrupts: should contain DSI interrupt
   - clocks: list of clock specifiers, must contain an entry for each required