pci node question

[Yoder Stuart-B08248]

There was refactoring change a while back that moved 
the interrupt map down into the virtual pci bridge.

example: 
42 /* controller at 0x200000 */
43 &pci0 {
44         compatible = "fsl,p2041-pcie", "fsl,qoriq-pcie-v2.2";
45         device_type = "pci";
46         #size-cells = <2>;
47         #address-cells = <3>;
48         bus-range = <0x0 0xff>;
49         clock-frequency = <33333333>;
50         interrupts = <16 2 1 15>;
51         pcie at 0 {
52                 reg = <0 0 0 0 0>;
53                 #interrupt-cells = <1>;
54                 #size-cells = <2>;
55                 #address-cells = <3>;
56                 device_type = "pci";
57                 interrupts = <16 2 1 15>;
58                 interrupt-map-mask = <0xf800 0 0 7>;
59                 interrupt-map = <
60                         /* IDSEL 0x0 */
61                         0000 0 0 1 &mpic 40 1 0 0
62                         0000 0 0 2 &mpic 1 1 0 0
63                         0000 0 0 3 &mpic 2 1 0 0
64                         0000 0 0 4 &mpic 3 1 0 0
65                         >;
66         };
67 };

Why was the interrupt-map moved here?

Do we really need the error interrupt specified twice?

Why is there a zeroed out reg property: reg = <0 0 0 0 0> ??

Thanks,
Stuart