dt-bindings: display: exynos: dsim: Add NXP i.MX8M Mini/Nano support

Samsung MIPI DSIM bridge can also be found in i.MX8M Mini/Nano 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>