arm: mach-orion5x: fix typo in compatible string of a .dts file

The orion5x-lacie-ethernet-disk-mini-v2.dts file was using
"marvell-orion5x-88f5182" as a compatible string, while it should have
been "marvell,orion5x-88f5182".

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>