dt-bindings: PCI: designware: Example update

Replace "ctrlreg" reg-name by "dbi" to be coherent with similar drivers,
however it still be compatible with any previous DT that uses the old
reg-name.

Replace the PCIe base address example by a real PCIe base address in use.

Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
[lorenzo.pieralisi@arm.com: updated commit log]
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh@kernel.org>