arm64: dts: rockchip: Add missing CM3i fallback compatible for Radxa E25

arm64: dts: rockchip: Add missing CM3i fallback compatible for Radxa E25

In order to function the Radxa E25 Carrier board, it is mandatory to
mount the Radxa CM3i module. 

Add Radxa CM3i compatible as fallback compatible to string to satisfy
the Module and Carrier board topology.

Fixes: 2bf2f4d9f673 ("arm64: dts: rockchip: Add Radxa CM3I E25")
Cc: Chukun Pan <amadeus@jmu.edu.cn>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Link: https://lore.kernel.org/r/20230123071654.73139-2-jagan@amarulasolutions.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>