ARM: dts: dove: Add definitions for PCIe error interrupts

First PCIe controller on Dove SoC reports error interrupt via IRQ 15
and second PCIe controller via IRQ 17.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>