xrp-example: fix IRQ mode of DSP #2 and #3 in DTS

Device IRQ delivery is the same for all DSPs in the example subsystem,
but the device-irq-mode property for DSP #2 and #3 is different in the
DTS. Make them all the same.
This fixes standalone tests running on DSP #2 and #3.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

xrp-example/xrp.dts

@@ -111,7 +111,7 @@
 		reg = <0x18000000 0x04000000
 		       0x30003000 0x00000200>;
 		device-irq = <0 2 16>; /* offset, bit#, IRQ# */
-		device-irq-mode = <1>;
+		device-irq-mode = <3>;
 		device-irq-host-offset = <0xcfffd108>;
 		queue-priority = <7 6 5>;
 		ranges = <0x00000000 0x00000000 0x20000000
@@ -131,7 +131,7 @@
 		reg = <0x1c000000 0x04000000
 		       0x30004000 0x00000200>;
 		device-irq = <0 2 16>; /* offset, bit#, IRQ# */
-		device-irq-mode = <1>;
+		device-irq-mode = <3>;
 		device-irq-host-offset = <0xcfffc10c>;
 		queue-priority = <7 6 5>;
 		ranges = <0x00000000 0x00000000 0x20000000