arm64: dts: marvell: cp110: add PPv2 port interrupts

Ports interrupts are used by the PPv2 driver when no PHY is connected to
a port. This patch adds a description of these interrupts.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
Tested-by: Marcin Wojtas <mw@semihalf.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>