getac/p470: Change COM3/COM4 IRQ to move it out of PCI IRQ ones.

The suggested IRQs 10 and 11 would conflict with PCI IRQ assignment
(10 for most interrupts on this board). Suggest IRQ 6 instead.

It's actually a noop since the code is commented out.

Change-Id: I0fdd8e2091d3dc79cfb1809a9ea5e1e841ca598a
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: http://review.coreboot.org/7476
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>

src/mainboard/getac/p470/devicetree.cb

@@ -119,11 +119,11 @@ chip northbridge/intel/i945
 					end
 					#device pnp 4e.2 on		# COM3
 					#         io 0x60 = 0x3e8
-					#        irq 0x70 = 11
+					#        irq 0x70 = 6
 					#end
 					#device pnp 4e.3 on		# COM4
 					#         io 0x60 = 0x2e8
-					#        irq 0x70 = 10
+					#        irq 0x70 = 6
 					#end
 					device pnp 4e.5 on		# Keyboard
 						io 0x60 = 0x60