ARM: dts: imx25.dtsi: DryIce security violation interrupt

The DryIce block on i.MX25 chipset uses two interrupts: A normal and a
security violation interrupt. Add the security violation interrupt to
the list, it is optional.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>