dtc recently added PCI bus checks. Fix these warnings.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>