arm: orion5x: correct IRQ used in dtsi for mv_cesa

The crypto functionality in the orion5x dtsi uses the Ethernet IRQ and
so things do not work and there is much grumbling at boot time.
The IRQ for the crypto should be 28, and not 22, and that is what this
patch corrects.

Signed-off-by: Alexander Clouter <alex@digriz.org.uk>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>