powerpc/fsl-booke: add the reg prop for pci bridge device node for T4/B4

powerpc/fsl-booke: add the reg prop for pci bridge device node for T4/B4

The reg property in the pci bridge device node is used to bind this
device node to the pci bridge device. Then all the pci devices under
this bridge could use the interrupt maps defined in this device node
to do the irq translation. So if this property is missed, the pci
traditional irq mechanism will not work.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>